Python Data Types

In this tutorial, you will learn about different data types you can use in Python.

Data types in Python

Each value in Python has a datatype. Since everything is an object in Python programming, information types are really classes, and factors are case (object) of these classes.

There are various data types in Python. Some of the important types are listed below.

Python Numbers

Integers, floating-point numbers, and complex numbers fall under Python numbers category. They are defined as int, float and complex classes in Python.

We can use the type() capacity to realize which class a variable or a value belongs to similarly, the instance() function is used to check if an article has a place with a specific class.

a = 5
print(a, "is of type", type(a))

a = 2.0
print(a, "is of type", type(a))

a = 1+2j
print(a, "is complex number?", isinstance(1+2j,complex))

Output

5 is of type <class 'int'>
2.0 is of type <class 'float'>
(1+2j) is complex number? True

Integers can be of any length, it is only limited by the memory available.

A floating-point number is precise up to 15 decimal spots. Whole number and coasting focuses are isolated by decimal focuses. 1 is a whole number, 1.0 is a floating-point number.

Complex numbers are written in the structure, x + yj, where x is the genuine part, and y is the nonexistent part. Here are some examples.

>>> a = 1234567890123456789
>>> a
1234567890123456789
>>> b = 0.1234567890123456789
>>> b
0.12345678901234568
>>> c = 1+2j
>>> c
(1+2j)

Notice that the float variable b got truncated.

Python List

The list is an ordered sequence of items. It is one of the most used data types in Python and is entirely adaptable. All the things in a rundown shouldn’t be of a similar kind.

Declaring a list is entirely straight forward. Items separated by commas are enclosed within brackets [ ].

a = [1, 2.2, 'python']

We can use the slicing operator [ ] to extract an item or a range of items from a list.

The index starts from 0 in Python.

a = [5,10,15,20,25,30,35,40]

# a[2] = 15
print("a[2] = ", a[2])

# a[0:3] = [5, 10, 15]
print("a[0:3] = ", a[0:3])

# a[5:] = [30, 35, 40]
print("a[5:] = ", a[5:])

Output

a[2] =  15
a[0:3] =  [5, 10, 15]
a[5:] =  [30, 35, 40]

Lists are mutable, meaning, the value of elements of a list can be altered.

a = [1, 2, 3]
a[2] = 4
print(a)

[1, 2, 4]

It is defined within parentheses () where items are separated by commas.

t = (5,'program', 1+3j)

We can use the slicing operator [] to extract items but we cannot change its value.

t = (5,'program', 1+3j)

# t[1] = 'program'
print("t[1] = ", t[1])

# t[0:3] = (5, 'program', (1+3j))
print("t[0:3] = ", t[0:3])

# Generates error
# Tuples are immutable
t[0] = 10

Output

t[1] =  program
t[0:3] =  (5, 'program', (1+3j))
Traceback (most recent call last):
  File "test.py", line 11, in <module>
    t[0] = 10
TypeError: 'tuple' object does not support item assignment

Python Strings

The string is a sequence of Unicode characters. We can use single quotes or double quotes to represent strings. Multi-line strings can be denoted using triple quotes, ''' or """.

s = "This is a string"
print(s)
s = '''A multiline
string'''
print(s)

Output

This is a string
A multiline
string

Just like a list and tuple, the slicing operator [ ] can be used with strings. Strings, however, are immutable.

s = 'Hello world!'

# s[4] = 'o'
print("s[4] = ", s[4])

# s[6:11] = 'world'
print("s[6:11] = ", s[6:11])

# Generates error
# Strings are immutable in Python
s[5] ='d'

Output

s[4] =  o
s[6:11] =  world
Traceback (most recent call last):
  File "<string>", line 11, in <module>
TypeError: 'str' object does not support item assignment

Python Set

Set is an unordered assortment of interesting things. Set is characterized by values isolated by a comma inside supports { }. items in a set are not ordered.

a = {5,2,3,1,4}

# printing set variable
print("a = ", a)

# data type of variable a
print(type(a))

Output

a =  {1, 2, 3, 4, 5}
<class 'set'>

We can perform set operations like union, intersection on two sets. Sets have unique values.

They eliminate duplicates.

a = {1,2,2,3,3,3}
print(a)

Output

{1, 2, 3}

Since the set is unordered collections, indexing has no meaning. Hence,

the slicing operator [] does not work.

>>> a = {1,2,3}
>>> a[1]
Traceback (most recent call last):
  File "<string>", line 301, in runcode
  File "<interactive input>", line 1, in <module>
TypeError: 'set' object does not support indexing

Python Dictionary

Dictionary is an unordered assortment of key-esteem sets.

It is generally used when we have a tremendous measure of information. Word references are improved for recovering information. We should realize the way to retrieve the value.

In Python, dictionaries are defined within braces {} with each item being a pair in the form key: value. Key and value can be of any type.

>>> d = {1:'value','key':2}
>>> type(d)
<class 'dict'>

We use the key to retrieve the respective value. But not the other way around.

d = {1:'value','key':2}
print(type(d))

print("d[1] = ", d[1]);

print("d['key'] = ", d['key']);

# Generates error
print("d[2] = ", d[2]);

Output

<class 'dict'>
d[1] =  value
d['key'] =  2
Traceback (most recent call last):
  File "<string>", line 9, in <module>
KeyError: 2

Conversion between data types

We can convert between different data types by using different type conversion

functions like int(), float(), str(), etc.

>>> float(5)
5.0

Conversion from float to int will truncate the value (make it closer to zero).

>>> int(10.6)
10
>>> int(-10.6)
-10

Conversion to and from string must contain compatible values.

>>> float('2.5')
2.5
>>> str(25)
'25'
>>> int('1p')
Traceback (most recent call last):
  File "<string>", line 301, in runcode
  File "<interactive input>", line 1, in <module>
ValueError: invalid literal for int() with base 10: '1p'

We can even convert one sequence to another.

>>> set([1,2,3])
{1, 2, 3}
>>> tuple({5,6,7})
(5, 6, 7)
>>> list('hello')
['h', 'e', 'l', 'l', 'o']

To convert to a dictionary, each element must be a pair:

>>> dict([[1,2],[3,4]])
{1: 2, 3: 4}
>>> dict([(3,26),(4,44)])
{3: 26, 4: 44}

Please feel free to give your comment if you face any difficulty here.

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