Type Casting in Python

Type Casting in Python#

Type casting is a method used to change the data type of a variable to match the operation you want to perform. In Python, you can use built-in functions like int(), str(), float(), etc., to achieve this.

Convert an Integer to a Float#

You can convert an integer to a float using the float() function.

Python 3.12.4 (tags/v3.12.4:8e8a4ba, Jun  6 2024, 19:30:16) [MSC v.1940 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> num = 100  # integer
>>> num = float(num)  # convert to float
>>> print(num)
100.0
>>> print(type(num))
<class 'float'>

Here, the integer 100 is converted to a float 100.0.

Convert a Float to an Integer#

You can convert a float to an integer using the int() function.

>>> num = 99.9  # float
>>> num = int(num)  # convert to integer
>>> print(num)
99
>>> print(type(num))
<class 'int'>

In this example, the float 99.9 is converted to the integer 99.

Convert a String Literal to an Integer and a Float#

You can convert a string literal to an integer and a float using int() and float().

>>> s = '132'  # string
>>> n = int(s)  # convert to integer
>>> print(n)
132
>>> print(type(n))
<class 'int'>
>>> f = float(s)  # convert to float
>>> print(f)
132.0
>>> print(type(f))
<class 'float'>

Here, the string '132' is converted to the integer 132 and the float 132.0.

Note on Converting Strings with Decimals#

If your string contains a decimal point, you can’t directly convert it to an integer. First, convert the string to a float and then to an integer.

>>> s = '132.564'  # string
>>> n = int(float(s))  # convert to integer
>>> print(n)
132
>>> print(type(n))
<class 'int'>

In this case, the string '132.564' is first converted to the float 132.564 and then to the integer 132.

Useful Built-in Functions#

Python comes with several built-in functions that you can use right away. Here are some of the most useful ones:

len() Function#

The len() function returns the number of characters in a string.

>>> print(len('hello'))
5

This function counts the number of characters in the string 'hello', which is 5.

bin() Function#

The bin() function converts an integer to its binary representation.

>>> num = 100
>>> print(bin(num))  # print binary number
0b1100100

The integer 100 is converted to its binary representation 0b1100100.

oct() Function#

The oct() function converts an integer to its octal representation.

>>> num = 100
>>> print(oct(num))  # print octal number
0o144

The integer 100 is converted to its octal representation 0o144.

hex() Function#

The hex() function converts an integer to its hexadecimal representation.

>>> num = 100
>>> print(hex(num))  # print hex number
0x64

The integer 100 is converted to its hexadecimal representation 0x64.

round() Function#

The round() function returns a floating-point number rounded to a specified number of decimal places.

>>> num = round(5.12345, 2)
>>> print(num)
5.12

Here, the number 5.12345 is rounded to 5.12.

id() Function#

The id() function returns a unique identifier for an object, which is its memory address.

>>> num = 5.12
>>> print(id(num))
1562211743472

The id() function returns the memory address of the object num.

These examples demonstrate how you can use type casting and built-in functions to manipulate and format data in Python.

Contents