What Is Casting In Python

Type casting, or just β€œcasting,” in Python refers to the process of converting one data type to another. For example, converting an integer to a string, a float to an integer, or a string to a list, etc.

The word β€œcasting” in programming comes from the metalworking process of β€œcasting,” in which molten metal is poured into a mold to make a certain shape. Similarly, when you cast a value in Python from one data type to another, you’re transforming the value into a new shape, or in this case, type, to meet your needs.

In addition to β€œcasting,” other terms that are used to describe the process of converting one data type to another in programming include type conversion, type coercion, or type transformation.

How To Do A Type Cast In Python

To do a type cast, Python offers some built-in functions which you can use to convert your desired datatype into another. The most common of those functions are displayed in the table below:

FunctionWhat It Does
int()Converts a value to an integer
float()Converts a value to a float
str()Converts a value (Usually an Integer or Float) to a string
list()Converts a value (Usually a set) to a list
tuple()Converts a value (Usually a List) to a tuple
set()Converts a value to a set
A showcase of the common casting functions in Python and what they do

From the list above, you can see that the name of the function is derived from the type a value is going to convert into.

Follow the links to go to an in-depth tutorial for each of the functions concerned or to learn alternatives to each method. Alternatively, you can also use the example I’m going to illustrate below to get a general idea of how the functions are used.

Python Example of Type Casting (string to int)

For this example, I’m going to demonstrate how to convert a string (of type str()) into an integer (of type int()). The illustration applies to the rest of the functions.

x = "10"
y = int(x)
print(y) # Output: 10

In the code above, x stores the value'10'. Although 10 itself is a number, the type of x is str() because the 10 is wrapped in quotes. On line 2, we use the int() function to convert the value of x into an integer, and we store the cast value in the y variable. Finally, we print the value to the console.

FAQ: what happens if you cast a blank variable in python?

If you try to cast a blank or None value in Python, you will get a TypeError telling you that a value to be cast must not be of type None. For example, if you try to cast a variable with a None value you’ll get the TypeError: int() argument must be a string, a bytes-like object or a real number, not 'NoneType'. This will also happen for other casting functions as well.

Thats it for this post, I’ll see you in others.

What Is Casting In Python

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