The int() function in Python is used to convert a given value into an integer. If no arguments are provided, it returns 0. It can handle different types of inputs, such as strings, floating-point numbers, and even numbers in different bases (like binary or hexadecimal).

Syntax

int([x], [base=10])

• x (optional): The value to be converted to an integer. It can be a string, float, or any object that implements the __int__() method.
• base (optional): The base of the number in string form. It defaults to 10 but can be set to other bases like 2, 8, or 16.

Return Value

• Returns an integer representation of the input.
• Raises a ValueError if the input cannot be converted to an integer.

Examples

1. Converting a floating-point number to an integer: The fractional part is truncated when converting a float to an integer.

   print(int(5.7))  # Output: 5
   

2. Converting a string to an integer: The string must represent a valid number, and it can also be in a specific base.

   print(int("42"))  # Output: 42
   print(int("1010", 2))  # Output: 10 (binary to decimal)
   print(int("1F", 16))  # Output: 31 (hexadecimal to decimal)
   

3. Using int() without arguments: When called without arguments, int() returns 0.

   print(int())  # Output: 0
   

4. Converting a float string to an integer: You cannot directly convert a float string to an integer. You would first convert the string to a float and then to an integer.

   print(int(float("5.9")))  # Output: 5
   

5. Converting with different number bases: You can pass strings representing numbers in different bases and specify the base.

   print(int("110", 2))  # Output: 6 (binary to decimal)
   print(int("77", 8))   # Output: 63 (octal to decimal)
   

6. Using int() with objects: Any object that defines the __int__() method can be passed to int().

   class MyNumber:
       def __int__(self):
           return 100
   
   num = MyNumber()
   print(int(num))  # Output: 100
   

Handling Errors

• If the input is a string and is not a valid number or if the base is not appropriate, int() raises a ValueError.
• If you pass a non-numeric string, Python will throw an error:

  print(int("hello"))  # Raises ValueError: invalid literal for int()
  

Summary

• The int() function converts a value into an integer.
• It can take optional arguments: a value and a base for string conversions.
• It supports conversions from strings, floats, and objects that define the __int__() method.
• If no argument is provided, it returns 0.