* 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.
for dealing with 'Numbers' we have: int, float, complex
'Strings' are there for handling Text content.
For conditional statements 'Booleans' are supported.
Lets start by covering one by one, firstly 'numbers'
All integer numbers irrespective of how big they are, are of 'int'
data type
Lets get started by opening IPython interpreter. Now we will create
some variables say:
a = 13
print a
To check the data type of any variable Python provides 'type' function
type(a)
b = 999999999999
print b
Floating point numbers comes under 'float'
p = 3.141592
type(p)
Python by default provides support to complex numbers.
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))
c.imag returns imaginary part of the variable
and similarly c.real gives real part.
Next we will look at Boolean data types:
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')
a.upper() returns a string will all letters capitalized.
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.
Opposite to this function, we also have 'join' function.
''.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'])
Thus we come to the end of this tutorial on introduction of Data types in
Python. In this tutorial we have learnt what are supported data types,
supported operations and performing simple IO operations in Python.
*** Notes