Python 3.3.0 (v3.3.0:bd8afb90ebf2, Sep 29 2012, 01:25:11) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "copyright", "credits" or "license()" for more information.

Algebraic expressions

>>> 2+3
5
>>> (3+1)*4
16
>>> 2**3
8
>>> 17%4
1
>>> 17//4
4
>>> min(2,3)
2
>>> max(2,6,3,4)
6

Boolean expressions

>>> 1 < 3
True
>>> 3 < 1
False
>>> 3 == 3
True
>>> 3 != 3
False
>>> 2+3 == 5
True
>>> (2+3) == 5
True

Boolean operators

>>> 2 < 3 and 3 < 4
True
>>> 2 == 4 or 3 < 4
True
>>> not (2==4)
True

Variables and assignment statement

>>> x = 3
>>> x
3
>>> x**2
9
>>> y = x**2
>>> y
9
>>> x3_A = 3
>>> x3_A
3

Strings

>>> s = 'hello!'
>>> s
'hello!'
>>> t = 'world'
>>> t
'world'
>>> s == t
False

String operators

>>> s + t
'hello!world'
>>> s = 'hello'
>>> t = 'world'
>>> s == t
False
>>> s + t
'helloworld'
>>> s + ' ' + t
'hello world'
>>> 3*s
'hellohellohello'
>>> 3*(s+' '+t+'!\n')
'hello world!\nhello world!\nhello world!\n'
>>> res = 3*(s+' '+t+'!\n')
>>> print(res)
hello world!
hello world!
hello world!

>>> res
'hello world!\nhello world!\nhello world!\n'
>>> '!' in res
True
>>> len(res)
39
>>> s in res
True
>>> 'll' in res
True
>>> s
'hello'
>>> t
'world'
>>> t[0]
'w'
>>> t[1]
'o'
>>> t[2]
'r'
>>> t[-1]
'd'
>>> t[-2]
'l'
>>> t[-3]
'r'

Lists and list operators

>>> lst = ['ant', 'bat', 'cat', 'dog']
>>> lst[0]
'ant'
>>> lst[1]
'bat'
>>> lst[-1]
'dog'
>>> 'ant' in lst
True
>>> 'elk' in lst
False
>>> 3*lst
['ant', 'bat', 'cat', 'dog', 'ant', 'bat', 'cat', 'dog', 'ant', 'bat', 'cat', 'dog']
>>> lst + lst
['ant', 'bat', 'cat', 'dog', 'ant', 'bat', 'cat', 'dog']
>>> min(lst)
'ant'
>>> max(lst)
'dog'
>>> lst
['ant', 'bat', 'cat', 'dog']
>>> lst[1] = 'bee'
>>> lst
['ant', 'bee', 'cat', 'dog']
>>> s
'hello'
>>> s[1] = 'a'
Traceback (most recent call last):
  File "<pyshell#66>", line 1, in <module>
    s[1] = 'a'
TypeError: 'str' object does not support item assignment

List methods

>>> lst
['ant', 'bee', 'cat', 'dog']
>>> lst.append('eel')
>>> lst
['ant', 'bee', 'cat', 'dog', 'eel']
>>> lst.count('dog')
1
>>> lst.remove('dog')
>>> lst
['ant', 'bee', 'cat', 'eel']

Function help()

>>> help(lst)
Help on list object:

class list(object)
 |  list() -> new empty list
 |  
 |  Methods defined here:
 |  
 |  __add__(...)
 |      x.__add__(y) <==> x+y
 |  
 |  __contains__(...)
 |      x.__contains__(y) <==> y in x
 |  
...
 |
 |  append(...)
 |      L.append(object) -> None -- append object to end
 |  
 |  clear(...)
 |      L.clear() -> None -- remove all items from L
 |  
 |  copy(...)
 |      L.copy() -> list -- a shallow copy of L
 |  
 |  count(...)
 |      L.count(value) -> integer -- return number of occurrences of value
 |  
 |  extend(...)
 |      L.extend(iterable) -> None -- extend list by appending elements from the iterable
 |  
 |  index(...)
 |      L.index(value, [start, [stop]]) -> integer -- return first index of value.
 |      Raises ValueError if the value is not present.
 |  
 |  insert(...)
 |      L.insert(index, object) -- insert object before index
 |  
 |  pop(...)
 |      L.pop([index]) -> item -- remove and return item at index (default last).
 |      Raises IndexError if list is empty or index is out of range.
 |  
 |  remove(...)
 |      L.remove(value) -> None -- remove first occurrence of value.
 |      Raises ValueError if the value is not present.
 |  
 |  reverse(...)
 |      L.reverse() -- reverse *IN PLACE*
 |  
 |  sort(...)
 |      L.sort(key=None, reverse=False) -> None -- stable sort *IN PLACE*
 |  
...

Modules

>>> import math
>>> help(math)
Help on module math:

NAME
    math

MODULE REFERENCE
    http://docs.python.org/3.3/library/math
    
    The following documentation is automatically generated from the Python
    source files.  It may be incomplete, incorrect or include features that
    are considered implementation detail and may vary between Python
    implementations.  When in doubt, consult the module reference at the
    location listed above.

DESCRIPTION
    This module is always available.  It provides access to the
    mathematical functions defined by the C standard.

FUNCTIONS
    acos(...)
        acos(x)
        
        Return the arc cosine (measured in radians) of x.
    
    acosh(...)
        acosh(x)
        
        Return the hyperbolic arc cosine (measured in radians) of x.
    
    asin(...)
        asin(x)
        
        Return the arc sine (measured in radians) of x.
...
    
    trunc(...)
        trunc(x:Real) -> Integral
        
        Truncates x to the nearest Integral toward 0. Uses the __trunc__ magic method.

DATA
    e = 2.718281828459045
    pi = 3.141592653589793

FILE
    /Library/Frameworks/Python.framework/Versions/3.3/lib/python3.3/lib-dynload/math.so


>>> math.sqrt(4)
2.0
>>> math.pi
3.141592653589793
>>> math.sin(math.pi)
1.2246467991473532e-16

Module turtle

>>> import turtle
>>> s = turtle.Screen()
>>> t = turtle.Turtle()
>>> t.forward(100)
>>> t.left(90)
>>> t.forward(50)
>>> t.pensize(3)
>>> t.color('red')
>>> t.circle(50,180)
>>> t.goto(0,0)
>>> t.undo()
>>> t.penup()
>>> t.goto(0,0)
>>> t.pendown()
>>> t.forward(20)
>>> t.setheading(180)
>>> t.circle(50)
>>> s.bye()


Writing programs


helloworld.py


>>> ================================ RESTART ================================
>>> 
hello world!


input.py


>>> ================================ RESTART ================================
>>> 
Please type your name: Ljubomir
Hello, Ljubomir!


oneway.py


>>> ================================ RESTART ================================
>>> 
Please type your name: Ljubomir
Enter your age: 46
Ljubomir is eligible to vote


twoway.py


>>> ================================ RESTART ================================
>>> 
Please type your name: Ljubomir
Enter your age: 46
Ljubomir is eligible to vote
Bye!
>>> ================================ RESTART ================================
>>> 
Please type your name: Marlena
Enter your age: 13
You will be eligible to vote in 5 years
Bye!


For loop and funtion range() 

>>> for i in range(10):
	print(i)

	
0
1
2
3
4
5
6
7
8
9
>>> for c in 'Ljubomir':
	print(c)

	
L
j
u
b
o
m
i
r
>>> lst = [5,3,1]
>>> for num in lst:
	print(num**2)

	
25
9
1
>>> for i in range(3,10):
	print(i)

	
3
4
5
6
7
8
9
>>> for i in range(3,10,2):
	print(i)

	
3
5
7
9
>>> for i in range(10,3,-2):
	print(i)

	
10
8
6
4
>>> lst
[5, 3, 1]
>>> for i in range(len(lst)):
	print(lst[i])

	
5
3
1

while loop

>>> while True:
	name = input('Enter your name: ')
	print('Hello',name)

	
Enter your name: Ljubomir
Hello Ljubomir
Enter your name: Ellie
Hello Ellie
Enter your name: Lena
Hello Lena
Enter your name: 
Traceback (most recent call last):
  File "<pyshell#143>", line 2, in <module>
    name = input('Enter your name: ')
KeyboardInterrupt
>>> 


User-defined funtions

functions.py


>>> ================================ RESTART ================================
>>> 
>>> help(f)
Help on function f in module __main__:

f(x)
    my first function

>>> f(2)
17
>>> ================================ RESTART ================================
>>> 
>>> avg(17,24)
20.5
>>> ================================ RESTART ================================
>>> 
>>> lst = [4,2,6,3,1,5,8]
>>> isSorted(lst)
False
>>> lst.sort()
>>> isSorted(lst)
True

File I/O

functions.py


>>> ================================ RESTART ================================
>>> 
>>> copy('test.txt', 'new.txt')
>>> infile = open('test.txt')
>>> infile.read(1)
'F'
>>> infile.read(1)
'i'
>>> infile.read(1)
'r'
>>> infile.read(5)
'st Li'
>>> infile.readline()
'ne.\n'
>>> infile.read()
'\nThird Line.\n'
>>> infile.close()
>>> outfile = open('new.txt', 'w')
>>> outfile.write('First line...')
13
>>> outfile.write('Still first line...')
19
>>> outfile.write('\nSecond and ... \nThird.\n')
24
>>> outfile.close()
>>> infile = open('new.txt')
>>> print(infile.read())
First line...Still first line...
Second and ... 
Third.

>>> infile.close()



Accessing WWW content


>>> from urllib.request import urlopen
>>> hekp(urlopen)
Traceback (most recent call last):
  File "<pyshell#1>", line 1, in <module>
    hekp(urlopen)
NameError: name 'hekp' is not defined
>>> help(urlopen)
Help on function urlopen in module urllib.request:

urlopen(url, data=None, timeout=<object object>, *, cafile=None, capath=None, cadefault=False)

>>> response = urlopen('http://reed.cs.depaul.edu/lperkovic/cs4hs2013/session.txt')
>>> type(response)
<class 'http.client.HTTPResponse'>
>>> response.getURL()
Traceback (most recent call last):
  File "<pyshell#5>", line 1, in <module>
    response.getURL()
AttributeError: 'HTTPResponse' object has no attribute 'getURL'
>>> response.getUrl()
Traceback (most recent call last):
  File "<pyshell#6>", line 1, in <module>
    response.getUrl()
AttributeError: 'HTTPResponse' object has no attribute 'getUrl'
>>> response.geturl()
'http://reed.cs.depaul.edu/lperkovic/cs4hs2013/session.txt'
>>> for header in response.getheaders():
	print(header)

	
('Server', 'Apache-Coyote/1.1')
('Accept-Ranges', 'bytes')
('ETag', 'W/"923-1375326995000"')
('Last-Modified', 'Thu, 01 Aug 2013 03:16:35 GMT')
('Content-Type', 'text/plain')
('Content-Length', '923')
('Date', 'Thu, 01 Aug 2013 12:14:26 GMT')
('Connection', 'close')
>>> raw = response.read()
>>> raw
b'pi@raspberrypi ~ $ ls\nDesktop  Documents  ocr_pi.png  python_games  Scratch\npi@raspberrypi ~ $ pwd\n/home/pi\npi@raspberrypi ~ $ ls ..\npi\npi@raspberrypi ~ $ ls /\nbin   dev  home  lost+found  mnt  proc  run   selinux  sys  usr\nboot  etc  lib   media       opt  root  sbin  srv      tmp  var\npi@raspberrypi ~ $ cd Documents/\npi@raspberrypi ~/Documents $ ls\nScratch Projects\npi@raspberrypi ~/Documents $ mkdir Python\\ Projects/\npi@raspberrypi ~/Documents $ ls\nPython Projects  Scratch Projects\npi@raspberrypi ~/Documents $ cd Python\\ Projects/\npi@raspberrypi ~/Documents/Python Projects $ ls\npi@raspberrypi ~/Documents/Python Projects $ nano test.txt\npi@raspberrypi ~/Documents/Python Projects $ ls\ntest.txt\npi@raspberrypi ~/Documents/Python Projects $ rm test.txt \npi@raspberrypi ~/Documents/Python Projects $ nano test.txt\npi@raspberrypi ~/Documents/Python Projects $ ls\ntest.txt\npi@raspberrypi ~/Documents/Python Projects $ \n'
>>> text = raw.decode()
>>> text
'pi@raspberrypi ~ $ ls\nDesktop  Documents  ocr_pi.png  python_games  Scratch\npi@raspberrypi ~ $ pwd\n/home/pi\npi@raspberrypi ~ $ ls ..\npi\npi@raspberrypi ~ $ ls /\nbin   dev  home  lost+found  mnt  proc  run   selinux  sys  usr\nboot  etc  lib   media       opt  root  sbin  srv      tmp  var\npi@raspberrypi ~ $ cd Documents/\npi@raspberrypi ~/Documents $ ls\nScratch Projects\npi@raspberrypi ~/Documents $ mkdir Python\\ Projects/\npi@raspberrypi ~/Documents $ ls\nPython Projects  Scratch Projects\npi@raspberrypi ~/Documents $ cd Python\\ Projects/\npi@raspberrypi ~/Documents/Python Projects $ ls\npi@raspberrypi ~/Documents/Python Projects $ nano test.txt\npi@raspberrypi ~/Documents/Python Projects $ ls\ntest.txt\npi@raspberrypi ~/Documents/Python Projects $ rm test.txt \npi@raspberrypi ~/Documents/Python Projects $ nano test.txt\npi@raspberrypi ~/Documents/Python Projects $ ls\ntest.txt\npi@raspberrypi ~/Documents/Python Projects $ \n'
>>> print(text)
pi@raspberrypi ~ $ ls
Desktop  Documents  ocr_pi.png  python_games  Scratch
pi@raspberrypi ~ $ pwd
/home/pi
pi@raspberrypi ~ $ ls ..
pi
pi@raspberrypi ~ $ ls /
bin   dev  home  lost+found  mnt  proc  run   selinux  sys  usr
boot  etc  lib   media       opt  root  sbin  srv      tmp  var
pi@raspberrypi ~ $ cd Documents/
pi@raspberrypi ~/Documents $ ls
Scratch Projects
pi@raspberrypi ~/Documents $ mkdir Python\ Projects/
pi@raspberrypi ~/Documents $ ls
Python Projects  Scratch Projects
pi@raspberrypi ~/Documents $ cd Python\ Projects/
pi@raspberrypi ~/Documents/Python Projects $ ls
pi@raspberrypi ~/Documents/Python Projects $ nano test.txt
pi@raspberrypi ~/Documents/Python Projects $ ls
test.txt
pi@raspberrypi ~/Documents/Python Projects $ rm test.txt 
pi@raspberrypi ~/Documents/Python Projects $ nano test.txt
pi@raspberrypi ~/Documents/Python Projects $ ls
test.txt
pi@raspberrypi ~/Documents/Python Projects $ 

>>>