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Python int() Function: Use, Syntax, and Examples

Python int() function: In this tutorial, we will learn about the int() function in Python with its use, syntax, parameters, returns type, and examples. By IncludeHelp Last updated : June 24, 2023

Python int() function

The int() function is a library function in Python, it is used to convert a string (that should contain a number/integer), number (integer, float) into an integer value.

Consider the below example with sample input/output values:

Input:
a = "1001"
print(int(a))
    
Output:
1001

Input:
a = 10.23
print(int(a))
    
Output:
10

Input:
a = "1110111"
print(int(a,2))
    
Output:
119

Syntax

The following is the syntax of int() function:

int(value, [base=10])

Parameter(s):

The following are the parameter(s):

• value – source value (string, number(integer/float)) to be converted in an integer value.
• base – it’s an optional parameter with default 10, it is used to define the base of source value, for example: if source string contains a binary value then we need to use base 2 to convert it into an integer.

Return Value

The return type of int() function is <type 'int'>, it returns an integer value.

Python int() Example 1: Convert values to integer

# python code to demonstrate example
# of int() function

a = 10.20
b = "1001"
c = "000"

print("a: ", a)
print("int(a): ", int(a))

print("b: ", b)
print("int(b): ", int(b))

print("c: ", c)
print("int(c): ", int(c))

Output

a:  10.2 
int(a):  10
b:  1001
int(b):  1001
c:  000
int(c):  0

Python int() Example 2: Convert different number systems to integer

Python code to convert different numbers systems (binary, octal and hexadecimal) to integer value (decimal).

# python code to demonstrate example
# of int() function

a = "10101010"
print("a: ", int(a,2))

a = "1234567"
print("a: ", int(a,8))

a = "5ABC12"
print("a: ", int(a,16))

Output

a:  170
a:  342391
a:  5946386

Python int() Example 3: Input integer value

The user input can be done by using the input() function and it returns a string. To input an integer number, we have to convert the value returned by the input() function into an integer using the int() function.

# Python int() Example - Input integer value

# Inputs
age = int(input("Enter age: "))
luckynumber = int(input("Enter you lucky number: "))

# Printing the values
print("age:", age)
print("luckynumber:", luckynumber)

Output

Enter age: 21
Enter you lucky number: 108
age: 21
luckynumber: 108

Python int() Example 4: ValueError

If the given value is not a valid integer, the function returns a ValueError.

# Python int() Example
# ValueError

x = int("Hello") # ValueError 

Output

Traceback (most recent call last):
  File "/home/main.py", line 4, in <module>
    x = int("Hello") # ValueError 
ValueError: invalid literal for int() with base 10: 'Hello'