Non-Programmer's Tutorial for Python 2.6/Print version

25 August 2014

##Python is easy to learn
print "Hello, World!"

Hello, World!

Halt!
Who Goes there? Josh
You may pass, Josh

python
python
Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.

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IDLE 1.2.1      
>>>

print "Hello, World!"

#!/usr/bin/env python2

#!/usr/bin/env python

#!/usr/bin/python

.py
-
_

ä
ö
ü
å
ß
print "Hello, World!"

Hello, World!

print "Jack and Jill went up a hill"
print "to fetch a pail of water;"
print "Jack fell down, and broke his crown,"
print "and Jill came tumbling after."

Jack and Jill went up a hill
to fetch a pail of water;
Jack fell down, and broke his crown,
and Jill came tumbling after.

print "Jack and Jill went up a hill"

Jack and Jill went up a hill

print "to fetch a pail of water;"

to fetch a pail of water;

print "Hello, World!"

print "Hello, World!"

print "2 + 2 is", 2 + 2
print "3 * 4 is", 3 * 4
print "100 - 1 is", 100 - 1
print "(33 + 2) / 5 + 11.5 is", (33 + 2) / 5 + 11.5

2 + 2 is 4
3 * 4 is 12
100 - 1 is 99
(33 + 2) / 5 + 11.5 is 18.5

print "2 + 2 is", 2 + 2

print "14 / 3 = ", 14 / 3
print "14 % 3 = ", 14 % 3
print
print "14.0 / 3.0 =", 14.0 / 3.0
print "14.0 % 3.0 =", 14.0 % 3.0
print
print "14.0 / 3 =", 14.0 / 3
print "14.0 % 3 =", 14.0 % 3
print
print "14 / 3.0 =", 14 / 3.0
print "14 % 3.0 =", 14 % 3.0
print

14 / 3 = 4
14 % 3 = 2

14.0 / 3.0 = 4.66666666667
14.0 % 3.0 = 2.0

14.0 / 3 = 4.66666666667
14.0 % 3 = 2.0

14 / 3.0 = 4.66666666667
14 % 3.0 = 2.0

# Not quite PI, but an incredible simulation
print 22.0 / 7.0    # 355/113 is even more incredible rational approx to PI

3.14285714286

# Output PI on the screen
print 22.0 / 7.0 # Well, just a good approximation

print "Something's rotten in the state of Denmark."
print "                -- Shakespeare"

Something's rotten in the state of Denmark.
                -- Shakespeare

# This is not quite true outside of USA
# and is based on my dim memories of my younger years
print "First Grade"
print "1 + 1 =", 1 + 1
print "2 + 4 =", 2 + 4
print "5 - 2 =", 5 - 2
print
print "Third Grade"
print "243 - 23 =", 243 - 23
print "12 * 4 =", 12 * 4
print "12 / 3 =", 12 / 3
print "13 / 3 =", 13 / 3, "R", 13 % 3
print
print "Junior High"
print "123.56 - 62.12 =", 123.56 - 62.12
print "(4 + 3) * 2 =", (4 + 3) * 2
print "4 + 3 * 2 =", 4 + 3 * 2
print "3 ** 2 =", 3 ** 2
print

First Grade
1 + 1 = 2
2 + 4 = 6
5 - 2 = 3

Third Grade
243 - 23 = 220
12 * 4 = 48
12 / 3 = 4
13 / 3 = 4 R 1

Junior High
123.56 - 62.12 = 61.44
(4 + 3) * 2 = 14
4 + 3 * 2 = 10
3 ** 2 = 9

print "Ada Lovelace", "born on", "November 27, 1852"

#Anything along these lines is acceptable:

#Addition
print "2 + 5 = ", 2 + 5

#subtraction
print "9 - 3 = ", 9 - 3

#multiplication
print "3 * 3 = ", 3 * 3

#division
print "90 / 5 = ", 90 / 5

#exponents
print "7 to the power of 2 (squared) = ", 7 ** 2

#remainder
print "the remainder when doing 22 / 9 = ", 22 % 9

print "Halt!"
user_reply = raw_input("Who goes there? ") 
print "You may pass,", user_reply

Halt!
Who goes there? Josh
You may pass, Josh

Halt!
Who goes there?

a = 123.4
b23 = 'Spam'
first_name = "Bill"
b = 432
c = a + b
print "a + b is", c
print "first_name is", first_name
print "Sorted Parts, After Midnight or", b23

a + b is 555.4
first_name is Bill
Sorted Parts, After Midnight or Spam

print "first_name"

first_name

print first_name

Bill

a = 1
print a
a = a + 1
print a
a = a * 2
print a

1
2
4

number = input("Type in a number: ")
text = raw_input("Type in a string: ")
print "number =", number
print "number is a", type(number)
print "number * 2 =", number * 2
print "text =", text
print "text is a", type(text)
print "text * 2 =", text * 2

Type in a Number: 12.34
Type in a String: Hello
number = 12.34
number is a <type 'float'>
number * 2 = 24.68
text = Hello
text is a <type 'str'>
text * 2 = HelloHello

>>> "This" + " " + "is" + " joined."
'This is joined.'
>>> "Ha, " * 5
'Ha, Ha, Ha, Ha, Ha, '
>>> "Ha, " * 5 + "ha!"
'Ha, Ha, Ha, Ha, Ha, ha!'
>>> 

print "This" + " " + "is" + " joined."
print "Ha, " * 5
print "Ha, " * 5 + "ha!"

# This program calculates rate and distance problems
print "Input a rate and a distance"
rate = input("Rate: ")
distance = input("Distance: ")
print "Time:", (distance / rate)

Input a rate and a distance
Rate: 5
Distance: 10
Time: 2

Input a rate and a distance
Rate: 3.52
Distance: 45.6
Time: 12.9545454545

# This program calculates the perimeter and area of a rectangle
print "Calculate information about a rectangle"
length = input("Length: ")
width = input("Width: ")
print "Area", length * width
print "Perimeter", 2 * length + 2 * width

Calculate information about a rectangle
Length: 4
Width: 3
Area 12
Perimeter 14

Calculate information about a rectangle
Length: 2.53
Width: 5.2
Area 13.156
Perimeter 15.46

# Converts Fahrenheit to Celsius
temp = input("Fahrenheit temperature: ")
print (temp - 32.0) * 5.0 / 9.0

Fahrenheit temperature: 32
0.0

Fahrenheit temperature: -40
-40.0

Fahrenheit temperature: 212
100.0

Fahrenheit temperature: 98.6
37.0

string1 = raw_input('String 1: ')
string2 = raw_input('String 2: ')
int1 = input('Integer 1: ')
int2 = input('Integer 2: ')
print string1 + string2
print int1 * int2

print "this is an exercise"
number_1 = input("please input the first number: ")
number_2 = input("Please input the second number: ")

string_1 = raw_input("Please input the first half of the word: ")
string_2 = raw_input("please input the second half of the word: ")

print "the words you input is '" + string_1 + string_2 + "'"
print "the result of the 2 numbers is:", number_1 * number_2

a = 0
while a < 10:
    a = a + 1
    print (a)

1
2
3
4
5
6
7
8
9
10

a = 1
s = 0
print ('Enter Numbers to add to the sum.')
print ('Enter 0 to quit.')
while a != 0:
    print 'Current Sum:', s
    a = input('Number? ')
    s = s + a
print 'Total Sum =', round(s, 2)

Enter Numbers to add to the sum.
Enter 0 to quit.
Current Sum: 0
Number? 200
Current Sum: 200
Number? -15.25
Current Sum: 184.75
Number? -151.85
Current Sum: 32.9
Number? 10.00
Current Sum: 42.9
Number? 0
Total Sum = 42.9

while 1 == 1:
   print "Help, I'm stuck in a loop."

==
<
# This program calculates the Fibonacci sequence
a = 0
b = 1
count = 0
max_count = 20
while count < max_count:
    count = count + 1
    # we need to keep track of a since we change it
    old_a = a
    old_b = b
    a = old_b
    b = old_a + old_b
    # Notice that the , at the end of a print statement keeps it
    # from switching to a new line
    print(old_a),

0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181

# Waits until a password has been entered.  Use Control-C to break out without
# the password

# Note that this must not be the password so that the 
# while loop runs at least once.
password = "no password"

# note that != means not equal
while password != "unicorn":
    password = raw_input("Password: ")
print "Welcome in"

Password: auo
Password: y22
Password: password
Password: open sesame
Password: unicorn
Welcome in

name = raw_input("What is your UserName: ")
password = raw_input("What is your Password: ")
print "To lock your computer type lock."
command = ""
input1 = ""
input2 = ""
while command != "lock":
    command = raw_input("What is your command: ")
while input1 != name:
    input1 = raw_input("What is your username: ")
while input2 != password:
    input2 = raw_input("What is your password: ")
print "Welcome back to your system!"

name = raw_input('Set name: ')
password = raw_input('Set password: ')
while 1 == 1:
    nameguess=passwordguess=key=""   # multiple assignment
    while (nameguess != name) or (passwordguess != password):
        nameguess = raw_input('Name? ')
        passwordguess = raw_input('Password? ')
    print "Welcome,", name, ". Type lock to lock."
    while key != "lock":
        key = raw_input("")

login = "john"
password = "tucker"
logged=2

while logged != 0:
    while login != "Phil":    
            login = raw_input("Login : ")
    while password != "McChicken":
            password = raw_input("Password: ")
    logged = 1

    print "Welcome!"
    print "To leave type lock "

    while logged == 1:
        leave = raw_input (">> ")
        if leave == "lock":
            logged = 0
print "Goodbye!!"

n = int(input("Type in a number: "))
if n < 0:
   print('The absolute value of', int(n), 'is: ', abs(-n))
else:
   print('The absolute value of', int(n), 'is: ', abs(n))

Type in a number: -14
The absolute value of -14 is:  14

Type in a number: 24
The absolute value of 24 is:  24

a = 0
while a < 10:
    a = a + 1
    if a > 5:
        print a, ">", 5
    elif a <= 7:
        print a, "<=", 7
    else:
        print "Neither test was true"

1 <= 7
2 <= 7
3 <= 7
4 <= 7
5 <= 7
6 > 5
7 > 5
8 > 5
9 > 5
10 > 5

# This Program Demonstrates the use of the == operator
# using numbers
print 5 == 6
# Using variables
x = 5
y = 8
print x == y

False
False

# Plays the guessing game higher or lower 

# This should actually be something that is semi random like the
# last digits of the time or something else, but that will have to
# wait till a later chapter.  (Extra Credit, modify it to be random
# after the Modules chapter)
number = 78
guess = 0

while guess != number: 
    guess = input("Guess a number: ")
    if guess > number:
        print "Too high"
    elif guess < number:
        print "Too low"

print "Just right"

Guess a number: 100
Too high
Guess a number: 50
Too low
Guess a number: 75
Too low
Guess a number: 87
Too high
Guess a number: 81
Too high
Guess a number: 78
Just right

# Asks for a number.
# Prints if it is even or odd

number = input("Tell me a number: ")
if number % 2 == 0:
    print number, "is even."
elif number % 2 == 1:
    print number, "is odd."
else:
    print number, "is very strange."

Tell me a number: 3
3 is odd.

Tell me a number: 2
2 is even.

Tell me a number: 3.14159
3.14159 is very strange.

# keeps asking for numbers until 0 is entered.
# Prints the average value.

count = 0
sum = 0.0
number = 1 # set to something that will not exit the while loop immediately.

print "Enter 0 to exit the loop"

while number != 0:
    number = input("Enter a number: ")
    if number != 0:
        count = count + 1
        sum = sum + number

print "The average was:", sum / count

Enter 0 to exit the loop
Enter a number: 3
Enter a number: 5
Enter a number: 0
The average was: 4.0

Enter 0 to exit the loop
Enter a number: 1
Enter a number: 4
Enter a number: 3
Enter a number: 0
The average was: 2.66666666667

# keeps asking for numbers until count numbers have been entered.
# Prints the average value.

sum = 0.0

print "This program will take several numbers then average them"
count = input("How many numbers would you like to average: ")
current_count = 0

while current_count < count:
    current_count = current_count + 1
    print "Number", current_count
    number = input("Enter a number: ")
    sum = sum + number

print "The average was:", sum / count

This program will take several numbers then average them
How many numbers would you like to average: 2
Number 1
Enter a number: 3
Number 2
Enter a number: 5
The average was: 4.0

This program will take several numbers then average them
How many numbers would you like to average: 3
Number 1
Enter a number: 1
Number 2
Enter a number: 4
Number 3
Enter a number: 3
The average was: 2.66666666667

number = 42
guess = 0
count = 0
while guess != number:
    count = count + 1
    guess = input('Guess a number: ')
    if guess > number:
        print 'Too high'
    elif guess < number:
        print 'Too low'
    else:
        print 'Just right'
        break
    if count > 2:
        print 'That must have been complicated.'
        break

number1 = input('1st number: ')
number2 = input('2nd number: ')
if number1 + number2 > 100:
    print 'That is a big number.'

name = raw_input('Your name: ')
if name == 'Ada':
    print 'That is a nice name.'
elif name == 'John Cleese' or name == 'Michael Palin':
    print '... some funny text.'
else:
    print 'You have a nice name.'

Height: 3
Width: 4
perimeter = 15

Height: 2
Width: 3
perimeter = 11

Height: 4
Width: 4
perimeter = 16

Height: 2
Width: 2
perimeter = 8

Height: 5
Width: 1
perimeter = 8

height = input("Height: ")
width = input("Width: ")
print "perimeter =", width + height + width + width

. . . . 

number = 5
while number > 1:
    print ".",
    number = number - 1
print

a = 23
b = -23

if a < 0:
    a = -a
if b < 0:
    b = -b                         #Or use the command: elif (if+else)
if a == b:
    print "The absolute values of", a, "and", b, "are equal"
else:
    print "The absolute values of", a, "and", b, "are different"

The absolute values of 23 and 23 are equal

def absolute_value(n):
    if n < 0:
        n = -n
    return n

a = 23
b = -23

if absolute_value(a) == absolute_value(b):
    print "The absolute values of", a, "and", b, "are equal"
else:
    print "The absolute values of", a, "and", b, "are different"

The absolute values of 23 and -23 are equal

def hello():
    print "Hello"

def area(w, h):
    return w * h

def print_welcome(name):
    print "Welcome", name

hello()
hello()

print_welcome("Fred")
w = 4
h = 5
print "width =", w, "height =", h, "area =", area(w, h)

Hello
Hello
Welcome Fred
width = 4 height = 5 area = 20

a = 4

def print_func():
    a = 17
    print "in  print_func a = ", a

print_func()
print "a = ", a,"which is global variable assigned prior to the function print_func"

in print_func a = 17
a = 4 which is global variable assigned prior to the function print_func

a_var = 10
b_var = 15
c_var = 25

def a_func(a_var):
    print ("in a_func a_var = ", a_var)
    b_var = 100 + a_var
    d_var = 2 * a_var
    print ("in a_func b_var = ", b_var)
    print ("in a_func d_var = ", d_var)
    print( "in a_func c_var = ", c_var)
    return b_var + 10

c_var = a_func(b_var)

print ("a_var = ", a_var)
print ("b_var = ", b_var)
print ("c_var = ", c_var)
print ("d_var = ", d_var)

 in a_func a_var =  15
 in a_func b_var =  115
 in a_func d_var =  30
 in a_func c_var =  25
 a_var =  10
 b_var =  15
 c_var =  125
 d_var = 

 Traceback (most recent call last):
  File "C:\Python24\def2", line 19, in -toplevel-
     print "d_var = ", d_var

 NameError: name 'd_var' is not defined

# converts temperature to fahrenheit or celsius

def print_options():
    print "Options:"
    print " 'p' print options"
    print " 'c' convert from celsius"
    print " 'f' convert from fahrenheit"
    print " 'q' quit the program"

def celsius_to_fahrenheit(c_temp):
    return 9.0 / 5.0 * c_temp + 32

def fahrenheit_to_celsius(f_temp):
    return (f_temp - 32.0) * 5.0 / 9.0

choice = "p"
while choice != "q":
    if choice == "c":
        temp = input("Celsius temperature: ")
        print "Fahrenheit:", celsius_to_fahrenheit(temp)
    elif choice == "f":
        temp = input("Fahrenheit temperature: ")
        print "Celsius:", fahrenheit_to_celsius(temp)
    elif choice == "p":
        print_options()
    choice = raw_input("option: ")

Options:
 'p' print options
 'c' convert from celsius
 'f' convert from fahrenheit
 'q' quit the program
option: c
Celsius temperature: 30 
Fahrenheit: 86.0
option: f
Fahrenheit temperature: 60
Celsius: 15.5555555556
option: q

# By Amos Satterlee
print
def hello():
    print 'Hello!'

def area(width, height):
    return width * height

def print_welcome(name):
    print 'Welcome,', name

name = raw_input('Your Name: ')
hello(),
print_welcome(name)
print
print 'To find the area of a rectangle,'
print 'enter the width and height below.'
print
w = input('Width: ')
while w <= 0:
    print 'Must be a positive number'
    w = input('Width: ')

h = input('Height: ')
while h <= 0:
    print 'Must be a positive number'
    h = input('Height: ')

print 'Width =', w, 'Height =', h, 'so Area =', area(w, h)

Your Name: Josh
Hello!
Welcome, Josh

To find the area of a rectangle,
enter the width and height below.

Width: -4
Must be a positive number
Width: 4
Height: 3
Width = 4 Height = 3 so Area = 12

def square(length):
    return length * length

def rectangle(width , height):
    return width * height

def circle(radius):
    return 3.14 * radius ** 2

def options():
    print
    print "Options:"
    print "s = calculate the area of a square."
    print "c = calculate the area of a circle."
    print "r = calculate the area of a rectangle."
    print "q = quit"
    print

print "This program will calculate the area of a square, circle or rectangle."
choice = "x"
options()
while choice != "q":
    choice = raw_input("Please enter your choice: ")
    if choice == "s":
        length = input("Length of square: ")
        print "The area of this square is", square(length)
        options()
    elif choice == "c":
        radius = input("Radius of the circle: ")
        print "The area of the circle is", circle(radius)
        options()
    elif choice == "r":
        width = input("Width of the rectangle: ")
        height = input("Height of the rectangle: ")
        print "The area of the rectangle is", rectangle(width, height)
        options()
    elif choice == "q":
        print "",
    else:
        print "Unrecognized option."
        options()

def mult(a, b):
    if b == 0:
        return 0
    rest = mult(a, b - 1)
    value = a + rest
    return value
result = mult(3, 2)
print "3 * 2 = ", result

3 * 2 =  6

def mult(a, b):
    if b == 0:
        return 0
    rest = mult(a, b - 1)
    value = a + rest
    return value

def mult(3, 2):
    if b == 0:
        return 0
    rest = mult(3, 2 - 1)
    value = 3 + rest
    return value

mult(3, 2)
3 + mult(3, 1)
3 + 3 + mult(3, 0)
3 + 3 + 0
3 + 3
6

#defines a function that calculates the factorial

def factorial(n):
    if n <= 1:
        return 1
    return n * factorial(n - 1)

print "2! =", factorial(2)
print "3! =", factorial(3)
print "4! =", factorial(4)
print "5! =", factorial(5)

2! = 2
3! = 6
4! = 24
5! = 120

def count_down(n):
    print n
    if n > 0:
        return count_down(n-1)

count_down(5)

5
4
3
2
1
0

# The comments below have been numbered as steps, to make explanation
# of the code easier. Please read according to those steps.
# (step number 1, for example, is at the bottom)

def mult(a, b): # (2.) This function will keep repeating itself, because....
    if b == 0:
        return 0
    rest = mult(a, b - 1) # (3.) ....Once it reaches THIS, the sequence starts over again and goes back to the top!
    value = a + rest
    return value # (4.) therefore, "return value" will not happen until the program gets past step 3 above

print "3 * 2 = ", mult(3, 2) # (1.) The "mult" function will first initiate here

# The "return value" event at the end can therefore only happen
# once b equals zero (b decreases by 1 everytime step 3 happens).
# And only then can the print command at the bottom be displayed.

# See it as kind of a "jump-around" effect. Basically, all you
# should really understand is that the function is reinitiated
# WITHIN ITSELF at step 3. Therefore, the sequence "jumps" back
# to the top.

# Another "jump-around" function example:

def factorial(n): # (2.) So once again, this function will REPEAT itself....
    if n <= 1:
        return 1
    return n * factorial(n - 1) # (3.) Because it RE-initiates HERE, and goes back to the top.

print "2! =", factorial(2) # (1.) The "factorial" function is initiated with this line
print "3! =", factorial(3)
print "4! =", factorial(4)
print "5! =", factorial(5)

# Another "jump-around", nice and easy:

def count_down(n): # (2.) Once again, this sequence will repeat itself....
    print n
    if n > 0:
        return count_down(n-1) # (3.) Because it restarts here, and goes back to the top

count_down(5) # (1.) The "count_down" function initiates here

which_one = input("What month (1-12)? ")
months = ['January', 'February', 'March', 'April', 'May', 'June', 'July',
          'August', 'September', 'October', 'November', 'December']

if 1 <= which_one <= 12:
    print "The month is", months[which_one - 1]

What month (1-12)? 3
The month is March

demolist = ["life", 42, "the universe", 6, "and", 9]
print "demolist = ",demolist
demolist.append("everything")
print "after 'everything' was appended demolist is now:"
print demolist
print "len(demolist) =", len(demolist)
print "demolist.index(42) =", demolist.index(42)
print "demolist[1] =", demolist[1]

# Next we will loop through the list
c = 0
while c < len(demolist):
    print "demolist[", c, "] =", demolist[c]
    c = c + 1

del demolist[2]
print "After 'the universe' was removed demolist is now:"
print demolist
if "life" in demolist:
    print "'life' was found in demolist"
else:
    print "'life' was not found in demolist"

if "amoeba" in demolist:
    print "'amoeba' was found in demolist"

if "amoeba" not in demolist:
    print "'amoeba' was not found in demolist"

demolist.sort()
print "The sorted demolist is", demolist

demolist =  ['life', 42, 'the universe', 6, 'and', 9]
after 'everything' was appended demolist is now:
['life', 42, 'the universe', 6, 'and', 9, 'everything']
len(demolist) = 7
demolist.index(42) = 1
demolist[1] = 42
demolist[ 0 ] = life
demolist[ 1 ] = 42
demolist[ 2 ] = the universe
demolist[ 3 ] = 6
demolist[ 4 ] = and
demolist[ 5 ] = 9
demolist[ 6 ] = everything
After 'the universe' was removed demolist is now:
['life', 42, 6, 'and', 9, 'everything']
'life' was found in demolist
'amoeba' was not found in demolist
The sorted demolist is [6, 9, 42, 'and', 'everything', 'life']

c = 0
while c < len(demolist):
    print 'demolist[', c, '] =', demolist[c]
    c = c + 1

"value"
menu_item = 0
namelist = []
while menu_item != 9:
    print "--------------------"
    print "1. Print the list"
    print "2. Add a name to the list"
    print "3. Remove a name from the list"
    print "4. Change an item in the list"
    print "9. Quit"
    menu_item = input("Pick an item from the menu: ")
    if menu_item == 1:
        current = 0
        if len(namelist) > 0:
            while current < len(namelist):
                print current, ".", namelist[current]
                current = current + 1
        else:
            print "List is empty"
    elif menu_item == 2:
        name = raw_input("Type in a name to add: ")
        namelist.append(name)
    elif menu_item == 3:
        del_name = raw_input("What name would you like to remove: ")
        if del_name in namelist:
            # namelist.remove(del_name) would work just as fine
            item_number = namelist.index(del_name)
            del namelist[item_number]
            # The code above only removes the first occurrence of
            # the name.  The code below from Gerald removes all.
            # while del_name in namelist:
            #       item_number = namelist.index(del_name)
            #       del namelist[item_number]
        else:
            print del_name, "was not found"
    elif menu_item == 4:
        old_name = raw_input("What name would you like to change: ")
        if old_name in namelist:
            item_number = namelist.index(old_name)
            new_name = raw_input("What is the new name: ")
            namelist[item_number] = new_name
        else:
            print old_name, "was not found"

print "Goodbye"

--------------------
1. Print the list
2. Add a name to the list
3. Remove a name from the list
4. Change an item in the list
9. Quit

Pick an item from the menu: 2
Type in a name to add: Jack

Pick an item from the menu: 2
Type in a name to add: Jill

Pick an item from the menu: 1
0 . Jack
1 . Jill

Pick an item from the menu: 3
What name would you like to remove: Jack

Pick an item from the menu: 4
What name would you like to change: Jill
What is the new name: Jill Peters

Pick an item from the menu: 1
0 . Jill Peters

Pick an item from the menu: 9
Goodbye

current = 0
if len(namelist) > 0:
    while current < len(namelist):
        print current, ".", namelist[current]
        current = current + 1
else:
    print "List is empty"

item_number = namelist.index(del_name)
del namelist[item_number]

old_name = raw_input("What name would you like to change: ")
if old_name in namelist:
    item_number = namelist.index(old_name)
    new_name = raw_input("What is the new name: ")
    namelist[item_number] = new_name
else:
   print old_name, "was not found"

## This program runs a test of knowledge

# First get the test questions
# Later this will be modified to use file io.
def get_questions():
    # notice how the data is stored as a list of lists
    return [["What color is the daytime sky on a clear day? ", "blue"],
            ["What is the answer to life, the universe and everything? ", "42"],
            ["What is a three letter word for mouse trap? ", "cat"]]

# This will test a single question
# it takes a single question in
# it returns True if the user typed the correct answer, otherwise False

def check_question(question_and_answer):
    # extract the question and the answer from the list
    question = question_and_answer[0]
    answer = question_and_answer[1]
    # give the question to the user
    given_answer = raw_input(question)
    # compare the user's answer to the testers answer
    if answer == given_answer:
        print "Correct"
        return True
    else:
        print "Incorrect, correct was:", answer
        return False

# This will run through all the questions
def run_test(questions):
    if len(questions) == 0:
        print "No questions were given."
        # the return exits the function
        return
    index = 0
    right = 0
    while index < len(questions):
        # Check the question
        if check_question(questions[index]):
            right = right + 1
            index = index + 1
        # go to the next question
        else:
            index = index + 1
    # notice the order of the computation, first multiply, then divide
    print "You got", right * 100 / len(questions),\
           "% right out of", len(questions)

# now let's run the questions

run_test(get_questions())

What color is the daytime sky on a clear day?green
Incorrect, correct was: blue
What is the answer to life, the universe and everything?42
Correct
What is a three letter word for mouse trap?cat
Correct
You got 66 % right out of 3

## This program runs a test of knowledge

questions = [["What color is the daytime sky on a clear day? ", "blue"],
             ["What is the answer to life, the universe and everything? ", "42"],
             ["What is a three letter word for mouse trap? ", "cat"],
             ["What noise does a truly advanced machine make?", "ping"]]

# This will test a single question
# it takes a single question in
# it returns True if the user typed the correct answer, otherwise False

def check_question(question_and_answer):
    # extract the question and the answer from the list
    question = question_and_answer[0]
    answer = question_and_answer[1]
    # give the question to the user
    given_answer = raw_input(question)
    # compare the user's answer to the testers answer
    if answer == given_answer:
        print "Correct"
        return True
    else:
        print "Incorrect, correct was:", answer
        return False

# This will run through all the questions

def run_test(questions):

    if len(questions) == 0:
        print "No questions were given."
        # the return exits the function
        return
    index = 0
    right = 0
    while index < len(questions):
        # Check the question
        if check_question(questions[index]):
            right = right + 1
        # go to the next question
        index = index + 1
    # notice the order of the computation, first multiply, then divide
    print "You got", right * 100 / len(questions),\
           "% right out of", len(questions)

#showing a list of questions and answers
def showquestions(questions):
    q = 0
    while q < len(questions):
        a = 0
        print "Q:" , questions[q][a]
        a = 1
        print "A:" , questions[q][a]
        q = q + 1

# now let's define the menu function
def menu():
    print "-----------------"
    print "Menu:"
    print "1 - Take the test"
    print "2 - View a list of questions and answers"
    print "3 - View the menu"
    print "5 - Quit"
    print "-----------------"

choice = "3"
while choice != "5":
    if choice == "1":
        run_test(questions)
    elif choice == "2":
        showquestions(questions)
    elif choice == "3":
        menu()
    print
    choice = raw_input("Choose your option from the menu above: ")

onetoten = range(1, 11)
for count in onetoten:
    print count

1
2
3
4
5
6
7
8
9
10

for count in range(1, 11):
    print count

>>> range(1, 10)
[1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> range(-32, -20)
[-32, -31, -30, -29, -28, -27, -26, -25, -24, -23, -22, -21]
>>> range(5,21)
[5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
>>> range(5)
[0, 1, 2, 3, 4]
>>> range(21, 5)
[]

demolist = ['life', 42, 'the universe', 6, 'and', 9, 'everything']
for item in demolist:
    print "The Current item is:",
    print item

The Current item is: life
The Current item is: 42
The Current item is: the universe
The Current item is: 6
The Current item is: and
The Current item is: 9
The Current item is: everything

list = [2, 4, 6, 8]
sum = 0
for num in list:
    sum = sum + num

print "The sum is:", sum

The sum is: 20

list = [4, 5, 7, 8, 9, 1, 0, 7, 10]
list.sort()
prev = list[0]
del list[0]
for item in list:
    if prev == item:
        print "Duplicate of", prev, "found"
    prev = item

Duplicate of 7 Found

l = [4, 5, 7, 8, 9, 1, 0, 7, 10]
print "l = [4, 5, 7, 8, 9, 1, 0, 7, 10]", "\t\tl:", l
l.sort()
print "l.sort()", "\t\tl:", l
prev = l[0]
print "prev = l[0]", "\t\tprev:", prev
del l[0]
print "del l[0]", "\t\tl:", l
for item in l:
    if prev == item:
        print "Duplicate of", prev, "found"
    print "if prev == item:", "\tprev:", prev, "\titem:", item
    prev = item
    print "prev = item", "\t\tprev:", prev, "\titem:", item

l = [4, 5, 7, 8, 9, 1, 0, 7, 10]        l: [4, 5, 7, 8, 9, 1, 0, 7, 10]
l.sort()                l: [0, 1, 4, 5, 7, 7, 8, 9, 10]
prev = l[0]             prev: 0
del l[0]                l: [1, 4, 5, 7, 7, 8, 9, 10]
if prev == item:        prev: 0         item: 1
prev = item             prev: 1         item: 1
if prev == item:        prev: 1         item: 4
prev = item             prev: 4         item: 4
if prev == item:        prev: 4         item: 5
prev = item             prev: 5         item: 5
if prev == item:        prev: 5         item: 7
prev = item             prev: 7         item: 7
Duplicate of 7 found
if prev == item:        prev: 7         item: 7
prev = item             prev: 7         item: 7
if prev == item:        prev: 7         item: 8
prev = item             prev: 8         item: 8
if prev == item:        prev: 8         item: 9
prev = item             prev: 9         item: 9
if prev == item:        prev: 9         item: 10
prev = item             prev: 10        item: 10

a = 1
b = 1
for c in range(1, 10):
    print a,
    n = a + b
    a = b
    b = n

1 1 2 3 5 8 13 21 34

a = 6
b = 7
c = 42
print 1, a == 6
print 2, a == 7
print 3, a == 6 and b == 7
print 4, a == 7 and b == 7
print 5, not a == 7 and b == 7
print 6, a == 7 or b == 7
print 7, a == 7 or b == 6
print 8, not (a == 7 and b == 6)
print 9, not a == 7 and b == 6

1 True
2 False
3 True
4 False
5 True
6 True
7 False
8 True
9 False

print 1, a == 6
print 2, a == 7

list = ["Life", "The Universe", "Everything", "Jack", "Jill", "Life", "Jill"]

# make a copy of the list. See the More on Lists chapter to explain what [:] means.
copy = list[:]
# sort the copy
copy.sort()
prev = copy[0]
del copy[0]

count = 0

# go through the list searching for a match
while count < len(copy) and copy[count] != prev:
    prev = copy[count]
    count = count + 1

# If a match was not found then count can't be < len
# since the while loop continues while count is < len
# and no match is found

if count < len(copy):
    print "First Match:", prev

First Match: Jill

>>> 'a' == ('a' or 'b')
>>> 'b' == ('a' or 'b')
>>> 'a' == ('a' and 'b')
>>> 'b' == ('a' and 'b')

>>> 'a' == ('a' or 'b')
True
>>> 'b' == ('a' or 'b')
False
>>> 'a' == ('a' and 'b')
False 
>>> 'b' == ('a' and 'b')
True

>>> 'a' == ('a' or 'b')  # Look at parentheses first, so evaluate expression "('a' or 'b')"
                           # 'a' is a nonempty string, so the first value is True
                           # Return that first value: 'a'
>>> 'a' == 'a'           # the string 'a' is equivalent to the string 'a', so expression is True
True

>>> 'b' == ('a' or 'b')  # Look at parentheses first, so evaluate expression "('a' or 'b')"
                           # 'a' is a nonempty string, so the first value is True
                           # Return that first value: 'a'
>>> 'b' == 'a'           # the string 'b' is not equivalent to the string 'a', so expression is False
False 

>>> 'a' == ('a' and 'b') # Look at parentheses first, so evaluate expression "('a' and 'b')"
                           # 'a' is a nonempty string, so the first value is True, examine second value
                           # 'b' is a nonempty string, so second value is True
                           # Return that second value as result of whole expression: 'b'
>>> 'a' == 'b'           # the string 'a' is not equivalent to the string 'b', so expression is False
False

>>> 'b' == ('a' and 'b') # Look at parentheses first, so evaluate expression "('a' and 'b')"
                           # 'a' is a nonempty string, so the first value is True, examine second value
                           # 'b' is a nonempty string, so second value is True
                           # Return that second value as result of whole expression: 'b'
>>> 'b' == 'b'           # the string 'b' is equivalent to the string 'b', so expression is True
True 

>>> 'a' == 'a' or 'a' == 'b' 
True
>>> 'b' == 'a' or 'b' == 'b' 
True
>>> 'a' == 'a' and 'a' == 'b' 
False
>>> 'b' == 'a' and 'b' == 'b'
False

## This programs asks a user for a name and a password.
# It then checks them to make sure the user is allowed in.

name = raw_input("What is your name? ")
password = raw_input("What is the password? ")
if name == "Josh" and password == "Friday":
    print "Welcome Josh"
elif name == "Fred" and password == "Rock":
    print "Welcome Fred"
else:
    print "I don't know you."

What is your name? Josh
What is the password? Friday
Welcome Josh

What is your name? Bill
What is the password? Money
I don't know you.

print "Try to guess my name!"
count = 3
name = "Tony"
guess = raw_input("What is my name? ")
while count > 1 and guess != name:
    print "You are wrong!"
    guess = raw_input("What is my name? ")
    count = count - 1

if guess != name:
    print "You are wrong!" # this message isn't printed in the third chance, so we print it now
    print "You ran out of chances."
    quit
else:
    print "Yes! My name is", name + "!"

def print_menu():
    print '1. Print Dictionary'
    print '2. Add definition'
    print '3. Remove word'
    print '4. Lookup word'
    print '5. Quit'
    print

words = {}
menu_choice = 0
print_menu()

while menu_choice != 5:
    menu_choice = input("Type in a number (1-5): ")
    if menu_choice == 1:
        print "Definitions:"
        for x in words.keys():
            print x, ": ", words[x]
        print
    elif menu_choice == 2:
        print "Add definition"
        name = raw_input("Word: ")
        means = raw_input("Definition: ")
        words[name] = means
    elif menu_choice == 3:
        print "Remove word"
        name = raw_input("Word: ")
        if name in words:
            del words[name]
            print name, " was removed."
        else:
            print name, " was not found."
    elif menu_choice == 4:
        print "Lookup Word"
        name = raw_input("Word: ")
        if name in words:
            print "The definition of ", name, " is: ", words[name]
        else:
            print "No definition for ", name, " was found."
    elif menu_choice != 5:
        print_menu()

1. Print Dictionary
2. Add definition
3. Remove word
4. Lookup word
5. Quit

Type in a number (1-5): 2
Add definition
Word: Python
Definition: A snake, a programming language, and a British comedy.
Type in a number (1-5): 2
Add definition
Word: Dictionary
Definition: A book where words are defined.
Type in a number (1-5): 1
Definitions:
Python: A snake, a programming language, and a British comedy.
Dictionary: A book where words are defined.

Type in a number (1-5): 4
Lookup Word
Word: Python
The definition of Python is: A snake, a programming language, and a British comedy.
Type in a number (1-5): 3
Remove Word
Word: Dictionary
Dictionary was removed.
Type in a number (1-5): 1
Definitions:
Python: A snake, a programming language, and a British comedy. 
Type in a number (1-5): 5

for x in words.keys():
    print x, ": ", words[x]

if name in words:
    del words[name]

if name in words:
    print "The definition of ", name, " is: ", words[name]

max_points = [25, 25, 50, 25, 100]
assignments = ['hw ch 1', 'hw ch 2', 'quiz   ', 'hw ch 3', 'test']
students = {'#Max': max_points}

def print_menu():
    print "1. Add student"
    print "2. Remove student"
    print "3. Print grades"
    print "4. Record grade"
    print "5. Print Menu"
    print "6. Exit"

def print_all_grades():
    print '\t',
    for i in range(len(assignments)):
        print assignments[i], '\t',
    print
    keys = students.keys()
    keys.sort()
    for x in keys:
        print x, '\t',
        grades = students[x]
        print_grades(grades)

def print_grades(grades):
    for i in range(len(grades)):
        print grades[i], '\t', '\t',
    print

print_menu()
menu_choice = 0
while menu_choice != 6:
    print
    menu_choice = input("Menu Choice (1-6): ")
    if menu_choice == 1:
        name = raw_input("Student to add: ")
        students[name] = [0] * len(max_points)
    elif menu_choice == 2:
        name = raw_input("Student to remove: ")
        if name in students:
            del students[name]
        else:
            print "Student:", name, "not found"
    elif menu_choice == 3:
        print_all_grades()
    elif menu_choice == 4:
        print "Record Grade"
        name = raw_input("Student: ")
        if name in students:
            grades = students[name]
            print "Type in the number of the grade to record"
            print "Type a 0 (zero) to exit"
            for i in range(len(assignments)):
                print i + 1, assignments[i], '\t',
            print
            print_grades(grades)
            which = 1234
            while which != -1:
                which = input("Change which Grade: ")
                which = which - 1
                if 0 <= which < len(grades):
                    grade = input("Grade: ")
                    grades[which] = grade
                elif which != -1:
                    print "Invalid Grade Number"
        else:
            print "Student not found"
    elif menu_choice != 6:
        print_menu()

1. Add student
2. Remove student
3. Print grades
4. Record grade
5. Print Menu
6. Exit

Menu Choice (1-6): 3
       hw ch 1         hw ch 2         quiz            hw ch 3         test 
#Max    25              25              50              25              100 

Menu Choice (1-6): 5
1. Add student
2. Remove student
3. Print grades
4. Record grade
5. Print Menu
6. Exit

Menu Choice (1-6): 1
Student to add: Bill

Menu Choice (1-6): 4
Record Grade
Student: Bill
Type in the number of the grade to record
Type a 0 (zero) to exit
1   hw ch 1     2   hw ch 2     3   quiz        4   hw ch 3     5   test 
0               0               0               0               0 
Change which Grade: 1
Grade: 25
Change which Grade: 2
Grade: 24
Change which Grade: 3
Grade: 45
Change which Grade: 4
Grade: 23
Change which Grade: 5
Grade: 95
Change which Grade: 0

Menu Choice (1-6): 3
       hw ch 1         hw ch 2         quiz            hw ch 3         test 
#Max    25              25              50              25              100
Bill    25              24              45              23              95 

Menu Choice (1-6): 6

def print_all_grades():
    print '\t',
    for i in range(len(assignments)):
        print assignments[i], '\t',
    print
    keys = students.keys()
    keys.sort()
    for x in keys:
        print x, '\t',
        grades = students[x]
        print_grades(grades)

import calendar
year = input("Type in the year number: ")
calendar.prcal(year)

Type in the year number: 2001

                                 2001                                  

       January                  February                    March      

Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
1  2  3  4  5  6  7                1  2  3  4                1  2  3  4     
8  9 10 11 12 13 14       5  6  7  8  9 10 11       5  6  7  8  9 10 11
15 16 17 18 19 20 21      12 13 14 15 16 17 18      12 13 14 15 16 17 18     
22 23 24 25 26 27 28      19 20 21 22 23 24 25      19 20 21 22 23 24 25     
29 30 31                  26 27 28                  26 27 28 29 30 31        

from calendar import prcal

year = input("Type in the year number: ")
prcal(year)

from time import time, ctime

prev_time = ""
while True:
    the_time = ctime(time())
    if prev_time != the_time:
        print "The time is:", ctime(time())
        prev_time = the_time

The time is: Sun Aug 20 13:40:04 2000
The time is: Sun Aug 20 13:40:05 2000
The time is: Sun Aug 20 13:40:06 2000
The time is: Sun Aug 20 13:40:07 2000

Traceback (innermost last):
 File "clock.py", line 5, in ?
    the_time = ctime(time())

KeyboardInterrupt

from random import randint
number = randint(0, 99)
guess = -1
while guess != number: 
    guess = input ("Guess a number: ")
    if guess > number:
        print "Too high"
    elif guess < number:
            print "Too low"
print "Just right"

>>> some_numbers = ['zero', 'one', 'two', 'three', 'four', 'five']
>>> some_numbers[0]
'zero'
>>> some_numbers[4]
'four'
>>> some_numbers[5]
'five'

>>> some_numbers[len(some_numbers) - 1]
'five'
>>> some_numbers[len(some_numbers) - 2]
'four'
>>> some_numbers[-1]
'five'
>>> some_numbers[-2]
'four'
>>> some_numbers[-6]
'zero'

>>> things = [0, 'Fred', 2, 'S.P.A.M.', 'Stocking', 42, "Jack", "Jill"]
>>> things[0]
0
>>> things[7]
'Jill'
>>> things[0:8]
[0, 'Fred', 2, 'S.P.A.M.', 'Stocking', 42, 'Jack', 'Jill']
>>> things[2:4]
[2, 'S.P.A.M.']
>>> things[4:7]
['Stocking', 42, 'Jack']
>>> things[1:5]
['Fred', 2, 'S.P.A.M.', 'Stocking']

>>> things[-4:-2]
['Stocking', 42]
>>> things[-4]
'Stocking'
>>> things[-4:6]
['Stocking', 42]

>>> things[:2]
[0, 'Fred']
>>> things[-2:]
['Jack', 'Jill']
>>> things[:3]
[0, 'Fred', 2]
>>> things[:-5]
[0, 'Fred', 2]

poem = ["<B>", "Jack", "and", "Jill", "</B>", "went", "up", "the",
        "hill", "to", "<B>", "fetch", "a", "pail", "of", "</B>",
        "water.", "Jack", "fell", "<B>", "down", "and", "broke",
        "</B>", "his", "crown", "and", "<B>", "Jill", "came",
        "</B>", "tumbling", "after"]

def get_bolds(text):
    true = 1
    false = 0
    ## is_bold tells whether or not we are currently looking at 
    ## a bold section of text.
    is_bold = false
    ## start_block is the index of the start of either an unbolded 
    ## segment of text or a bolded segment.
    start_block = 0
    for index in range(len(text)):
        ## Handle a starting of bold text
        if text[index] == "<B>":
            if is_bold:
                print "Error: Extra Bold"
            ## print "Not Bold:", text[start_block:index]
            is_bold = true
            start_block = index + 1
        ## Handle end of bold text
        ## Remember that the last number in a slice is the index 
        ## after the last index used.
        if text[index] == "</B>":
            if not is_bold:
                print "Error: Extra Close Bold"
            print "Bold [", start_block, ":", index, "]", text[start_block:index]
            is_bold = false
            start_block = index + 1

get_bolds(poem)

Bold [ 1 : 4 ] ['Jack', 'and', 'Jill']
Bold [ 11 : 15 ] ['fetch', 'a', 'pail', 'of']
Bold [ 20 : 23 ] ['down', 'and', 'broke']
Bold [ 28 : 30 ] ['Jill', 'came']

>>> a = [1, 2, 3]
>>> b = a
>>> print b
[1, 2, 3]
>>> b[1] = 10
>>> print b
[1, 10, 3]
>>> print a
[1, 10, 3]

>>> a = [1, 2, 3]
>>> b = a * 2
>>> print a
[1, 2, 3]
>>> print b
[1, 2, 3, 1, 2, 3]
>>> a[1] = 10
>>> print a
[1, 10, 3]
>>> print b
[1, 2, 3, 1, 2, 3]

>>> a = [1, 2, 3]
>>> b = a[:]
>>> b[1] = 10
>>> print a
[1, 2, 3]
>>> print b
[1, 10, 3]

>>> import copy
>>> a = [[1, 2, 3], [4, 5, 6]]
>>> b = a[:]
>>> c = copy.deepcopy(a)
>>> b[0][1] = 10
>>> c[1][1] = 12
>>> print a
[[1, 10, 3], [4, 5, 6]]
>>> print b
[[1, 10, 3], [4, 5, 6]]
>>> print c
[[1, 2, 3], [4, 12, 6]]

def shout(string):
    for character in string:
        print "Gimme a " + character
        print "'" + character + "'"
shout("Lose")

def middle(string):
    print "The middle character is:", string[len(string) / 2]

middle("abcdefg")
middle("The Python Programming Language")
middle("Atlanta")

Gimme a L
'L'
Gimme a o
'o'
Gimme a s
's'
Gimme a e
'e'
The middle character is: d
The middle character is: r
The middle character is: a

def to_upper(string):
    ## Converts a string to upper case
    upper_case = ""
    for character in string:
        if 'a' <= character <= 'z':
            location = ord(character) - ord('a')
            new_ascii = location + ord('A')
            character = chr(new_ascii)
        upper_case = upper_case + character
    return upper_case

print to_upper("This is Text")

THIS IS TEXT

>>> # Integer to String
>>> 2
2
>>> repr(2)
'2'
>>> -123
-123
>>> repr(-123)
'-123'
>>> `123`
'123'
>>> # String to Integer
>>> "23"
'23'
>>> int("23")
23
>>> "23" * 2
'2323'
>>> int("23") * 2
46
>>> # Float to String
>>> 1.23
1.23
>>> repr(1.23)
'1.23'
>>> # Float to Integer
>>> 1.23
1.23
>>> int(1.23)
1
>>> int(-1.23)
-1
>>> # String to Float
>>> float("1.23")
1.23
>>> "1.23" 
'1.23'
>>> float("123")
123.0
>>> `float("1.23")`
'1.23'

>>> repr(1)
'1'
>>> repr(234.14)
'234.14'
>>> repr([4, 42, 10])
'[4, 42, 10]'
>>> `[4, 42, 10]`
'[4, 42, 10]'

>>> v = eval('123')
>>> print v, type(v)
123 <type 'int'>
>>> v = eval('645.123')
>>> print v, type(v)
645.123 <type 'float'>
>>> v = eval('[1, 2, 3]')
>>> print v, type(v)
[1, 2, 3] <type 'list'>

>>> "This is a bunch of words".split()
['This', 'is', 'a', 'bunch', 'of', 'words']
>>> text = "First batch, second batch, third, fourth"
>>> text.split(",")
['First batch', ' second batch', ' third', ' fourth']

>>> list = text.split(",")
>>> len(list)
4
>>> list[-1]
' fourth'
>>> list = text.split(",", 2)
>>> len(list)
3
>>> list[-1]
' third, fourth'

# This program requires an excellent understanding of decimal numbers
def to_string(in_int):
    """Converts an integer to a string"""
    out_str = ""
    prefix = ""
    if in_int < 0:
        prefix = "-"
        in_int = -in_int
    while in_int / 10 != 0:
        out_str = chr(ord('0') + in_int % 10) + out_str
        in_int = in_int / 10
    out_str = chr(ord('0') + in_int % 10) + out_str
    return prefix + out_str

def to_int(in_str):
    """Converts a string to an integer"""
    out_num = 0
    if in_str[0] == "-":
        multiplier = -1
        in_str = in_str[1:]
    else:
        multiplier = 1
    for x in range(0, len(in_str)):
        out_num = out_num * 10 + ord(in_str[x]) - ord('0')
    return out_num * multiplier

print to_string(2)
print to_string(23445)
print to_string(-23445)
print to_int("14234")
print to_int("12345")
print to_int("-3512")

2
23445
-23445
14234
12345
-3512

# Write a file
out_file = open("test.txt", "w")
out_file.write("This Text is going to out file\nLook at it and see!")
out_file.close()

# Read a file
in_file = open("test.txt", "r")
text = in_file.read()
in_file.close()

print text

This Text is going to out file
Look at it and see!

def print_numbers(numbers):
    print "Telephone Numbers:"
    for x in numbers.keys():
        print "Name:", x, "\tNumber:", numbers[x]
    print

def add_number(numbers, name, number):
    numbers[name] = number

def lookup_number(numbers, name):
    if name in numbers:
        return "The number is " + numbers[name]
    else:
        return name + " was not found"

def remove_number(numbers, name):
    if name in numbers:
        del numbers[name]
    else:
        print name," was not found"

def load_numbers(numbers, filename):
    in_file = open(filename, "r")
    for in_line in in_file:
        in_line = in_line.rstrip('\n') #Eliminate end of line or enter        
        name, number = in_line.split(",")
        numbers[name] = number
    in_file.close()

def save_numbers(numbers, filename):
    out_file = open(filename, "w")
    for x in numbers.keys():
        out_file.write(x + "," + numbers[x] + "\n")
    out_file.close()

def print_menu():
    print '1. Print Phone Numbers'
    print '2. Add a Phone Number'
    print '3. Remove a Phone Number'
    print '4. Lookup a Phone Number'
    print '5. Load numbers'
    print '6. Save numbers'
    print '7. Quit'
    print

phone_list = {}
menu_choice = 0
print_menu()
while True:
    menu_choice = input("Type in a number (1-7): ")
    if menu_choice == 1:
        print_numbers(phone_list)
    elif menu_choice == 2:
        print "Add Name and Number"
        name = raw_input("Name: ")
        phone = raw_input("Number: ")
        add_number(phone_list, name, phone)
    elif menu_choice == 3:
        print "Remove Name and Number"
        name = raw_input("Name: ")
        remove_number(phone_list, name)
    elif menu_choice == 4:
        print "Lookup Number"
        name = raw_input("Name: ")
        print lookup_number(phone_list, name)
    elif menu_choice == 5:
        filename = raw_input("Filename to load: ")
        load_numbers(phone_list, filename)
    elif menu_choice == 6:
        filename = raw_input("Filename to save: ")
        save_numbers(phone_list, filename)
    elif menu_choice == 7:
        break
    else:
        print_menu()

print "Goodbye"

1. Print Phone Numbers
2. Add a Phone Number
3. Remove a Phone Number
4. Lookup a Phone Number
5. Load numbers
6. Save numbers
7. Quit

Type in a number (1-7): 2
Add Name and Number
Name: Jill
Number: 1234
Type in a number (1-7): 2
Add Name and Number
Name: Fred
Number: 4321
Type in a number (1-7): 1
Telephone Numbers:
Name: Jill     Number: 1234
Name: Fred     Number: 4321

Type in a number (1-7): 6
Filename to save: numbers.txt
Type in a number (1-7): 7
Goodbye

1. Print Phone Numbers
2. Add a Phone Number
3. Remove a Phone Number
4. Lookup a Phone Number
5. Load numbers
6. Save numbers
7. Quit

Type in a number (1-7): 5
Filename to load: numbers.txt
Type in a number (1-7): 1
Telephone Numbers:
Name: Jill     Number: 1234
Name: Fred     Number: 4321

Type in a number (1-7): 7
Goodbye

def load_numbers(numbers, filename):
    in_file = open(filename, "r")
    while True:
        in_line = in_file.readline()
        if not in_line:
            break
        in_line = in_line[:-1]
        name, number = in_line.split(",")
        numbers[name] = number
    in_file.close()
def save_numbers(numbers, filename):
    out_file = open(filename, "w")
    for x in numbers.keys():
        out_file.write(x + "," + numbers[x] + "\n")
    out_file.close()

assignments = ['hw ch 1', 'hw ch 2', 'quiz   ', 'hw ch 3', 'test']
students = { }

def load_grades(gradesfile):
    inputfile = open(gradesfile, "r")
    grades = [ ]
    while True:
        student_and_grade = inputfile.readline()
        student_and_grade = student_and_grade[:-1]
        if not student_and_grade:
            break
        else:
            studentname, studentgrades = student_and_grade.split(",")
            studentgrades = studentgrades.split(" ")
            students[studentname] = studentgrades
    inputfile.close()
    print "Grades loaded."

def save_grades(gradesfile):
    outputfile = open(gradesfile, "w")
    for i in students.keys():
        outputfile.write(i + ",")
        for x in students[i]:
            outputfile.write(x + ",") #added missing comma
        outputfile.write("\n")
    outputfile.close()
    print "Grades saved."

def print_menu():
    print "1. Add student"
    print "2. Remove student"
    print "3. Load grades"
    print "4. Record grade"
    print "5. Print grades"
    print "6. Save grades"
    print "7. Print Menu"
    print "9. Quit"

def print_all_grades():
    keys = students.keys()
    if keys:
        keys.sort()
        print '\t',
        for i in range(len(assignments)):
            print assignments[i], '\t',
        print
        for x in keys:
            print x, '\t',
            grades = students[x]
            print_grades(grades)
    else:
        print "There are no grades to print."

def print_grades(grades):
    for i in range(len(grades)):
        print grades[i], '\t',
    print

print_menu()
menu_choice = 0
while menu_choice != 9:
    print
    menu_choice = input("Menu Choice: ")
    if menu_choice == 1:
        name = raw_input("Student to add: ")
        students[name] = [0] * len(assignments)
    elif menu_choice == 2:
        name = raw_input("Student to remove: ")
        if name in students:
            del students[name]
        else:
            print "Student:", name, "not found"
    elif menu_choice == 3:
        gradesfile = raw_input("Load grades from which file? ")
        load_grades(gradesfile)
    elif menu_choice == 4:
        print "Record Grade"
        name = raw_input("Student: ")
        if name in students:
            grades = students[name]
            print "Type in the number of the grade to record"
            print "Type a 0 (zero) to exit"
            for i in range(len(assignments)):
                print i + 1, assignments[i], '\t',
            print
            print_grades(grades)
            which = 1234
            while which != -1:
                which = input("Change which Grade: ")
                which = which - 1
                if 0 <= which < len(grades):
                    grade = raw_input("Grade: ") # Change from input() to raw_input() to avoid an error when saving
                    grades[which] = grade
                elif which != -1:
                    print "Invalid Grade Number"
        else:
            print "Student not found"
    elif menu_choice == 5:
        print_all_grades()
    elif menu_choice == 6:
        gradesfile = raw_input("Save grades to which file? ")
        save_grades(gradesfile)
    elif menu_choice != 9:
        print_menu()

print "Type Control C or -1 to exit"
number = 1
while number != -1:
    number = int(raw_input("Enter a number: "))
    print "You entered:", number

Traceback (innermost last):
 File "try_less.py", line 4, in ?
    number = int(raw_input("Enter a number: "))</syntaxhighlight>

ValueError: invalid literal for int(): @#&

print "Type Control C or -1 to exit"
number = 1
while number != -1:
    try:
        number = int(raw_input("Enter a number: "))
        print "You entered:", number
    except ValueError:
        print "That was not a number."

# Program by Mitchell Aikens 2012
# No copyright.
import math

def main():
	success = 0
	while (success == 0):
		try:
			epact()
			success = 1
		except ValueError:
			print "Error. Please enter an integer value."
			year = 0
		except NameError:
			print "Error. Please enter an integer value."
			year = 0
		except SyntaxError:
			print "Error. Please enter an integer value."
			year = 0
		finally:
			print "Program Complete"

def epact():

    year = int(input("What year is it?\n"))
    C = year/100
    epactval = (8 + (C/4) - C + ((8*C + 13)/25) + 11 * (year%19))%30
    print "The Epact is: ",epactval

main()

#Program By Mitchell Aikens 2012
#Not copyright.

def main():
    try:
        number = int(input("Please enter a number.\n"))
        half = number/2
        print "Half of the number you entered is ",half
    except NameError:
        print "Error."
    except ValueError:
        print "Error."
    except SyntaxError:
        print "Error."
    finally:
        print "I am executing the finally clause."

main()

Please enter a number.
t
Error.
I am executing the finally clause.

TODO = ['errors',
        'how to make modules',
        'more on loops',
        'more on strings',
        'more on dictionaries',
        'file io',
        'how to use online help',
        'try',
        'pickle',
        'break and continue']

Operation	Symbol	Example
Power (exponentiation)	`**`	`5 ** 2 == 25`
Multiplication	`*`	`2 * 3 == 6`
Division	`/`	`14 / 3 == 4`
Remainder (modulo)	`%`	`14 % 3 == 2`
Addition	`+`	`1 + 2 == 3`
Subtraction	`-`	`4 - 3 == 1`

Operation	Symbol	Example
Repetition	`*`	`"i" * 5 == "iiiii"`
Concatenation	`+`	`"Hello, " + "World!" == "Hello, World!"`

operator	function
`<`	less than
`<=`	less than or equal to
`>`	greater than
`>=`	greater than or equal to
`==`	equal
`!=`	not equal
`<>`	another way to say not equal (old style, not recommended)

example	explanation
`demolist[2]`	accesses the element at index 2
`demolist[2] = 3`	sets the element at index 2 to be 3
`del demolist[2]`	removes the element at index 2
`len(demolist)`	returns the length of `demolist`
`"value" in demolist`	is True if `"value"` is an element in `demolist`
`"value" not in demolist`	is True if `"value"` is not an element in `demolist`
`demolist.sort()`	sorts `demolist`
`demolist.index("value")`	returns the index of the first place that `"value"` occurs
`demolist.append("value")`	adds an element `"value"` at the end of the list
`demolist.remove("value")`	removes the first occurrence of value from `demolist` (same as `del demolist[demolist.index("value")]`)

True	False
True	False
1	0
Numbers other than zero	The string 'None'
Nonempty strings	Empty strings
Nonempty lists	Empty lists
Nonempty dictionaries	Empty dictionaries

		0		1		2		...		-2		-1
		↓		↓		↓		↓		↓		↓		↓
text =	"		S		T		R		I		N		G		"
		↑												↑
		[:												:]

text[1:4]	→	"TRI"
text[:5]	→	"STRIN"
text[:-1]	→	"STRIN"
text[-4:]	→	"RING"
text[2]	→	"R"
text[:]	→	"STRING"
text[::-1]	→	"GNIRTS"

Authors

Contributors

Front matter

Other resources

Intro

First things first

Installing Python

Linux, BSD and Unix users

Mac users

Windows users

Interactive Mode

Creating and Running Programs

Running Python Programs in Unix

Program file names

Using Python from the command line

Where to get help

Python documentation

Python user community

Hello, World

What you should know

Printing

Terminology

Expressions

Talking to humans (and other intelligent beings)

Examples

Exercises

Footnotes

Who Goes There?

Input and Variables

Assignment

Examples

Exercises

Count to 10

While loops

Infinite loops

Examples

Exercises

Decisions

If statement

Examples

Exercises

Debugging

What is debugging?

What should the program do?

What does the program do?

How do I fix the program?

Defining Functions

Creating Functions

Variables in functions

Complex example

Examples

Exercises

Advanced Functions Example

Recursion

Examples

Lists

Variables with more than one value

More features of lists

Examples

Exercises

For Loops

Boolean Expressions

A note on Boolean Operators

Examples

Exercises

Dictionaries

Using Modules

Exercises

More on Lists

Revenge of the Strings

Slicing strings (and lists)

Examples

File IO

Exercises

Dealing with the imperfect

...or how to handle errors

Exercises

The End

FAQ

License