Python has five
standard data types −
- Numbers
- Dictionary
- Boolean
- Set
- Sequence
1. Python
Numbers
Number data types store
numeric values.
Python supports four
different numerical types −
- int (signed integers)
- long (long integers, they can also
be represented in octal and hexadecimal)
- float (floating point real values)
- complex (complex numbers)
To
verify the type of any object in Python, use the type( ) function
>>> type(10)
<class 'int'>
>>> a=11
>>>
print(type(a))
<class 'int'>
2. Python
Strings
Strings in Python are
identified as a contiguous set of characters represented in the quotation
marks. Python allows for either pairs of single or double quotes.
Example:
str = 'Hello World!'
Subsets of strings can
be taken using the slice operator ([ ] and [:] ) with indexes starting at 0 in
the beginning of the string and working their way from -1 at the end.
Example:
print str[0] # Prints first character of the string
print str[2:5] # Prints characters starting from 3rd to
5th
print str[2:] # Prints string starting from 3rd
character
The plus (+) sign is
the string concatenation operator and the asterisk (*) is the repetition
operator.
Example:
print str +
"TEST" # Prints concatenated string
3. Python
Lists
Lists are the most
versatile of Python's compound data types.
A list contains items
separated by commas and enclosed within square brackets ([]).
Lists are similar to
arrays in C. One difference between them is that all the items belonging to a
list can be of different data type.
The values stored in a
list can be accessed using the slice operator ([ ] and [:]) with indexes
starting at 0 in the beginning of the list and working their way to end -1. The
plus (+) sign is the list concatenation operator, and the asterisk (*) is the
repetition operator.
Example:
list = [ 'abcd', 786 ,
2.23, 'john', 70.2 ]
print list[0] # Prints first element of the list
print list[1:3] # Prints elements starting from 2nd till
3rd
print list[2:] # Prints elements starting from 3rd
element
print list * 2 # Prints list two times
4. Python
Tuples
A tuple is another
sequence data type that is similar to the list. A tuple consists of a number of
values separated by commas. Unlike lists, however, tuples are enclosed within
parentheses.
The main differences
between lists and tuples is that Lists are enclosed in brackets ( [ ] ) and
their elements and size can be changed, while tuples are enclosed in
parentheses ( ( ) ) and cannot be updated. Tuples can be thought of as read-only lists.
Example:
my_tuple = (1, 2, 3, 4,
5)
>>> print(my_tuple)
(1, 2, 3, 4, 5)
5. Python
Dictionary
A dictionary is an object that stores a collection of data. Each element
in a dictionary has two parts: a key and a value. A key is used to locate a specific
value. Dictionary elements are commonly referred to as key-value pairs.
A dictionary created by enclosing the elements inside a set of curly
braces ( {} ). An element consists of a key, followed by a colon, followed by a
value. The elements are separated by commas.
Example:
phonebook = {'Ashraf':'555−1111', 'Amjad':'555−2222', 'Anwar':'555-3333'}
The values in a dictionary can be objects of any type, but the keys must
be immutable objects. For example, keys can be strings, integers,
floating-point values, or tuples. Keys cannot be lists or any other type of
immutable object.
6. Python boolean
Python boolean type is one of the built-in data types
provided by Python, which are defined by the True or False keywords. Generally,
it is used to represent the truth values of the expressions.
Numbers can be used as bool values by using Python’s built-in bool() method.
Any integer, floating-point number, or complex number having zero as a value is
considered as False, while if they are having value as any positive or negative
number then it is considered as True.
Example:
var1 = 0
print(bool(var1))
var2 = 1
print(bool(var2))
var3 = -9.7
print(bool(var3))
Output:
False
True
True
7. Python Set
In Python, Set is an unordered collection of data type that is
iterable, mutable and has no duplicate elements. The order of elements in a set
is undefined though it may consist of various elements.
Sets can be created by using the built-in set() function with
an iterable object or a sequence by placing the sequence inside curly braces,
separated by ‘comma’. Type of elements in a set need not be the same, various
mixed-up data type values can also be passed to the set.
Example:
set1 = set("GeeksForGeeks") # using string
set2 = set(["Geeks", "For", "Geeks"])
#using list
set3 = set([1, 2, 'Geeks', 4, 'For', 6, 'Geeks']) #using mixed values