* Data Types

*** Outline

***** Introduction

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    Welcome friends. 

    In this tutorial we shall look at data types available in Python and 

    how to perform simple Input and Output operations. 

    data type

    To check the data type of any variable Python provides 'type' function

    Floating point numbers comes under 'float'

    p = 3.141592

    type(p)

    c = 3+4j 

    c is a complex number. 'j' is used to specify the imaginary part.

    type(c)

    Python also provides basic functions for their manipulations like

    abs(c) will return the absolute value of c(sqrt(a^2 + b^2))

    Its a primitive datatype having one of two values: True or False.

    t = True

    print t

    Python is case sensitive language, so True with 'T' is boolean type but

    true with 't' would be a variable. 

    f = not True

    we can do binary operation like 'or' and 'not' with these variables

    f or t

    f and t

    in case of multiple binary operations to make sure of precedence use 

    'brackets ()'

    a = False

    b = True

    c = True

    (a and b) or c    

    True

    first a and b is evaluated and then the 'or' statement

    a and (b or c)

    False

    Now we shall look at Python Strings.

    In python anything enclosed inside quotes(single or double) is a string

    so 

    a = 'This is a string'

    print a

    b = "This too!"

    print b

    c = '''This one too!'''

    print c

    d = """And one more."""

    print d

    Similar to lists we covered earlier even string elements can be accessed 

    via index numbers starting from 0

    print a[0]    

    print a[5]

    will 

    To access last element we can use a[-1] which is one of Pythons feature.

    print a[-1]

    len function works with the strings also as it does with the arrays and 

    returns length of the string.

    One thing to notice about the string variables is that they are 

    immutable, that is

    a[0] = 't'

    will throw an error

    Some of methods available for string are:

    a.startswith('Thi')

    returns true if initial of the string is same

    similarly there is endswith

    a.endswith('ING')

    and a.lower() returns a string with all smaller case letters.

    As we have seen earlier use of split function, it returns the list after

    splitting the string, so

    a.split()

    will give list with three elements.

    ''.join(['a','b','c']) will return a joined string of the list we pass

    to it. Since join is performed on '' that is empty string we get 'abc'

    if we do something like

    '-'.join(['a','b','c'])

    Python. In this tutorial we have learnt what are supported data types, 

    supported operations and performing simple IO operations in Python.

*** Notes