Python Programming/Print version

Note: current version of this book can be found at http://en.wikibooks.org/wiki/Python_Programming

>>> a,b = 0,1
>>> print b
1
>>> while b < 100:
...   a,b = b,(a+b)
...   print b,
... 
1 2 3 5 8 13 21 34 55 89 144

dir()
dir(object)
locals()
$ sudo apt-get update  # This will update the software repository
$ sudo apt-get install python   # This one will actually install python

$ python
Python 2.3.4 (#2, Aug 29 2004, 02:04:10) 
[GCC 3.3.4 (Debian 1:3.3.4-9)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>

>>>
1+1
2
>>> 5
5
>>> print 5*7
35
>>> "hello" * 4
'hellohellohellohello'
>>> "hello".__class__
<type 'str'>

if 1:
  print "True"
print "Done"

>>> if 1:
...   print "True"
... print "Done"
  File "<stdin>", line 3
    print "Done"
        ^
SyntaxError: invalid syntax

if 1:
  print "True"

print "Done"

>>> if 1:
...   print "True"
...
True
>>> print "Done"
Done
>>>

print "Hello, world!"

print "Hello, world!",

Hello, world!
python -i hello.py

#!/usr/bin/python

name = 'Ada Lovelace'
print "Goodbye, " + name + '!'

"will not work'
#!/usr/bin/python

print 'Please enter your name.'
name = raw_input()
print 'How are you, ' + name + '?'

raw_input()
#!/usr/bin/python

print "What is your mass in kilograms?",
mass_kg = int(raw_input())
mass_stone = mass_kg * 2.2 / 14
print "You weigh " + str(mass_stone) + " stone."

"What is your mass in kilograms?"
print
print
int()
int()
str(
)
"You weigh " + mass_stone
`
print "You weigh " + str(mass_stone) + " stone."

$ ./kg2stone

What is your mass in kilograms? 65
You weigh 10.214285714285714 stone.

print "You weigh %.1f stone." % (mass_stone)

$ ./kg2stone

What is your mass in kilograms? 65
You weigh 10.2 stone.

>>> print 'I am a single quoted string'
I am a single quoted string
>>> print "I am a double quoted string"
I am a double quoted string
>>> print """I am a triple quoted string"""
I am a triple quoted string

#!/usr/bin/python

print 'Spam' + 'Eggs'
print 'Ni!' * 10

#!/usr/bin/python

string = "And now for something completely different."
print string[22:42]

#!/usr/bin/python

spam = ['eggs', 42, 'bacon']
print spam
print spam[0]

#!/usr/bin/python

spam = ['eggs', 42, 'bacon']
print "Before modification:", spam
spam[1] = 5
print "After modification:", spam

#!/usr/bin/python

spam = ['eggs', 1, 'bacon']
print "Length: ", len(spam)
spam[len(spam):] = [9]
print spam

#!/usr/bin/python

mylist1 = []
mylist2 = []
mystring = "breakfast"
mylist1[0:] = mystring
print mylist1
mylist2[0:] = [mystring]
print mylist2

#['b','r','e','a','k','f','a','s','t']
#['breakfast']

#!/usr/bin/python

spam = ('eggs', 42, 'bacon')
print spam
print spam[0]

'bob'.upper

'bob'.upper()

dir()
Python 2.3.4 (#53, Oct 18 2004, 20:35:07) [MSC v.1200 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> dir()
['__builtins__', '__doc__', '__name__']

type()
>>> type(__builtins__)
<type 'module'>

dir()
>>> dir(__builtins__)
['ArithmeticError', ... 'copyright', 'credits', ... 'help', ... 'license', ... 'zip']
>>>

>>> dir()
['__builtins__', '__doc__', '__name__']
>>> name = "Bob"
>>> import math
>>> dir()
['__builtins__', '__doc__', '__name__', 'math', 'name']

>>> math
<module 'math' (built-in)>

>>> dir(math)
['__doc__', '__name__', 'acos', 'asin', 'atan', 'atan2', 'ceil', 'cos', 'cosh', 'degrees', 'e',
'exp', 'fabs', 'floor', 'fmod', 'frexp', 'hypot', 'ldexp', 'log', 'log10', 'modf', 'pi', 'pow',
'radians', 'sin', 'sinh', 'sqrt', 'tan', 'tanh']
>>>

__name__
math
>>> print __name__
__main__
>>> print math.__name__
math
>>> print math.__doc__
This module is always available.  It provides access to the
mathematical functions defined by the C standard.
>>> math.pi
3.1415926535897931

'foo' works, and
"moo" works as well,
     but
'bar" does not work, and
"baz' does not work either.
"quux'' is right out.

'''foo''' works, and
"""moo""" works as well,
     but
'"'bar'"' does not work, and
"""baz''' does not work either.
'"'quux"'" is right out.

(10, 'Mary had a little lamb')

10, 'whose fleece was as white as snow'

('this is a stupid tuple',)

['abc', 1,2,3]

{ 'hello': 'world', 'weight': 'African or European?' }

((((((((('bob',),['Mary', 'had', 'a', 'little', 'lamb']), { 'hello' : 'world' } ),),),),),),)

//
>>> x = 5
>>> type(x)
<type 'int'>
>>> x = 187687654564658970978909869576453
>>> type(x)
<type 'long'>
>>> x = 1.34763
>>> type(x)
<type 'float'>
>>> x = 5 + 2j
>>> type(x)
<type 'complex'>

5/2
5/2.
5./2
__future__ import
>>> 5/2
2
>>>5/2.
2.5
>>>5./2
2.5
>>> from __future__ import division
>>> 5/2
2.5
>>> 5//2
2

>>> a = 'hello'; b = 'hello' # Assign 'hello' to a and b.
>>> print a == b             # True
True
>>> print a == 'hello'       #
True
>>> print a == "hello"       # (choice of delimiter is unimportant)
True
>>> print a == 'hello '      # (extra space)
False
>>> print a == 'Hello'       # (wrong case)
False

>>> c = 'a'
>>> c + 'b'
'ab'
>>> c * 5
'aaaaa'

>>> x = 'hello'
>>> y = 'll'
>>> x in y
False
>>> y in x
True

>>> s = "Xanadu"
>>> s[1]
'a'

>>> s[-4]
'n'

>>> s[1:4]
'ana'

>>> print s
>>> s[0] = 'J'
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: object does not support item assignment
>>> s[1:3] = "up"
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: object does not support slice assignment
>>> print s

Xanadu
Xanadu

>>> s[2:]
'nadu'
>>> s[:3]
'Xan'
>>> s[:]
'Xanadu'

>>> print s[-2:]
'du'

Element:     1     2     3     4
Index:    0     1     2     3     4
         -4    -3    -2    -1

>>> '2YK'.istitle()
False
>>> '2Yk'.istitle()
True
>>> '2Y K'.istitle()
True

>>> s = 'Hello, wOrLD'
>>> s
'Hello, wOrLD'
>>> s.title()
'Hello, World'
>>> s.swapcase()
'hELLO, WoRld'
>>> s.upper()
'HELLO, WORLD'
>>> s.lower()
'hello, world'
>>> s.capitalize()
'Hello, world'

>>> s = 'Hello, world'
>>> s.count('l') # print the number of 'l's in 'Hello, World' (3)
3

>>> s = '\t Hello, world\n\t '
>>> print s
         Hello, world

>>> print s.strip()
Hello, world
>>> print s.lstrip()
Hello, world
        # ends here
>>> print s.rstrip()
         Hello, world

import string
s = 'www.wikibooks.org'
print s
print s.strip('w')                 # Removes all w's from outside
print s.strip(string.lowercase)    # Removes all lowercase letters from outside
print s.strip(string.printable)    # Removes all printable characters

www.wikibooks.org
.wikibooks.org
.wikibooks.

>>> s = 'foo'
>>> s
'foo'
>>> s.ljust(7)
'foo    '
>>> s.rjust(7)
'    foo'
>>> s.center(7)
'  foo  '

>>> seq = ['1', '2', '3', '4', '5']
>>> ' '.join(seq)
'1 2 3 4 5'
>>> '+'.join(seq)
'1+2+3+4+5'

>>> seq = [1,2,3,4,5]
>>> ' '.join(map(str, seq))
'1 2 3 4 5'

>>> s = 'Hello, world'
>>> s.find('l')
2
>>> s[s.index('l'):]
'llo, world'
>>> s.rfind('l')
10
>>> s[:s.rindex('l')]
'Hello, wor'
>>> s[s.index('l'):s.rindex('l')]
'llo, wor'

>>> 'Hello, world'.replace('o', 'X')
'HellX, wXrld'

string = 'Hello, world'
newString = string.replace('o', 'X')
print string
print newString

'Hello, world'
'HellX, wXrld'

s = 'abcdefg\tabc\ta'
print s
print len(s)
t = s.expandtabs()
print t
print len(t)

abcdefg abc     a
13
abcdefg abc     a
17

v = s.expandtabs(4)
print v
print len(s)

abcdefg abc a
13

>>> s = 'Hello, world'
>>> s.split()
['Hello, ', 'world']
>>> s.split('l')
['He', '', 'o, wor', 'd']

>>> s = """
... One line
... Two lines
... Red lines
... Blue lines
... Green lines
... """
>>> s.split('\n')
['', 'One line', 'Two lines', 'Red lines', 'Blue lines', 'Green lines', '']
>>> s.splitlines()
['', 'One line', 'Two lines', 'Red lines', 'Blue lines', 'Green lines']

[ 1,2,3,"This is a list",'c',Donkey("kong") ]

listOfWords = ["this","is","a","list","of","words"]

>>> listOfWords = ["this","is","a","list","of","words"]
>>> items = [ word[0] for word in listOfWords ]
>>> print items
['t', 'i', 'a', 'l', 'o', 'w']

>>> item = [x+y for x in 'flower' for y in 'pot']
>>> print item
['fp', 'fo', 'ft', 'lp', 'lo', 'lt', 'op', 'oo', 'ot', 'wp', 'wo', 'wt', 'ep', 'eo', 'et', 'rp', 'ro', 'rt']

>>> print x, y
r t

>>> zeros=[0]*5
>>> print zeros
[0, 0, 0, 0, 0]

>>> foos=['foo']*8
>>> print foos
['foo', 'foo', 'foo', 'foo', 'foo', 'foo', 'foo', 'foo']

listoflists=[ [0]*4 ] *5

>>> listoflists=[ [0]*4 ] *5
>>> print listoflists
[[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]]
>>> listoflists[0][2]=1
>>> print listoflists
[[0, 0, 1, 0], [0, 0, 1, 0], [0, 0, 1, 0], [0, 0, 1, 0], [0, 0, 1, 0]]

>>> innerlist=[0]*4
>>> listoflists=[innerlist]*5
>>> print listoflists
[[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]]
>>> innerlist[2]=1
>>> print listoflists
[[0, 0, 1, 0], [0, 0, 1, 0], [0, 0, 1, 0], [0, 0, 1, 0], [0, 0, 1, 0]]

>>> listoflists=[[0]*4 for i in range(5)]
>>> print listoflists
[[0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]]
>>> listoflists[0][2]=1
>>> print listoflists
[[0, 0, 1, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 0, 0]]

>>> len([1,2,3])
3
>>> a = [1,2,3,4]
>>> len( a )
4

>>> [1,2] + [3,4]
[1, 2, 3, 4]

>>> a = [1,2,3]
>>> b = [4,5,6]
>>> a.extend(b)
>>> print a
[1, 2, 3, 4, 5, 6]

>>> p=[1,2]
>>> p.append([3,4])
>>> p
[1, 2, [3, 4]]
>>> # or
>>> print p
[1, 2, [3, 4]]

>>> list = [2, 4, "usurp", 9.0,"n"]
>>> list[2]
'usurp'
>>> list[3:]
[9.0, 'n']

>>> list[1] = 17
>>> list
[2, 17, 'usurp', 9.0,'n']

>>> list[1:4] = ["opportunistic", "elk"]
>>> list
[2, 'opportunistic', 'elk', 'n']

>>> list[:0] = [3.14,2.71]
>>> list
[3.14, 2.71, 2, 'opportunistic', 'elk', 'n']

>>> list[:] = ['new', 'list', 'contents']
>>> list
['new', 'list', 'contents']

>>> list[:2] = ('element',('t',),[])
>>> list
['element', ('t',), [], 'contents']

>>> original = [1, 'element', []]
>>> list_copy = original[:]
>>> list_copy
[1, 'element', []]
>>> list_copy.append('new element')
>>> list_copy
[1, 'element', [], 'new element']
>>> original
[1, 'element', []]

>>> list_copy[2].append('something')
>>> original
[1, 'element', ['something']]

>>> [1,2] == [1,2]
True
>>> [1,2] == [3,4]
False

>>> list = [2, 3, 1, 'a', 'b']
>>> list.sort()
>>> list
[1, 2, 3, 'a', 'b']

>>> list = [1, 2, 3]
>>> list.

Python Programming/Print version

From Wikibooks, the open-content textbooks collection

Table of contents

Introduction

Learning to program in Python

Python concepts

Rocking the Python (Modules)

References

Authors

License

Overview

Getting Python

Installing Python in Windows

Installing Python on Mac

Installing Python on Ubuntu

Interactive mode

Creating Python programs

Hello, World!

Windows

Mac

Linux

Result

Interactive mode

Exercises

Notes

Using variables and math

Using a variable

raw_input()

Simple math

Formatting output

Strings and arrays

Strings

Lists

Tuples

Basic syntax

Case Sensitivity

Spaces and tabs don't mix

Objects

Scope

Namespaces

Data types

Numbers

Strings

String manipulation

String operations

Equality

Numerical

Containment

Indexing and Slicing

String constants

String methods

is*

title, upper, lower, swapcase, capitalize

count

strip, rstrip, lstrip

ljust, rjust, center

join

find, index, rfind, rindex

replace

expandtabs

split, splitlines

Lists

About lists in Python

List notation

List creation shortcuts

Operations on lists

List Attributes

Combining lists

Getting pieces of lists (slices)

Comparing lists

Sorting lists

List methods

append(x)