What is Python:
Python is an interpreted, object-oriented, high-level programming language with dynamic semantics.
Python Interactive shell
At first we will learn python interactive shell uses. You can start interpreter from IDLE.
The Python interpreter is a command line program:
>>> print 'hello world' Hello world >>> 2+2 4 >>> 50-20 30 >>> 5*5 25 >>> 30/6 5 >>> x = 5 >>> y = 10 >>> print x+y 15
Single line comment: A single line comment starts with the number sign (#) character:
# This is a comment print('Hello')
Multiline comment: Multiple lines can be created by repeating the number sign several times:
# This is a comment # second line # 3rd line print('Hello')
Variables in Python can hold text and numbers.
var = 2 hello = 2.5 country = 'Bangladesh'
type() is a function:
>>> country = "Bangladesh" >>> print country Bangladesh >>> type(country) <type 'str'> >>> var = 2.5 >>> print var 2.5 >>> type(var) <type 'float'>
if you want to exit from python interactive shell
String uses: Strings in Python can be defined using quote symbols
>>> country = "Bangladesh" >>> print country Bangladesh >>> str = "Adam's" >>> print str Adam's >>> hello = 'Adam\'s' >>> print hello Adam's >>>
Accesing array elements: You may access character elements of a string using the brackets symbol. Computers start counting from zero
>>> country = "Bangladesh" >>> print country  B >>> print country  n >>>
String length: builtin function len()
>>> len(country) 10 >>> print country  h
Let us look at some string operations. We can add two string
>>> country = 'Bangla' + 'desh' >>> country 'Bangladesh' >>>
The string did not have anything, that i can do with find() method.
>>> country.find('Bangla') 0 >>> country.find('desh') 6 >>>