Python Casting

Specify a Variable Type

There may be times when you want to specify a type on to a variable. This can be done with casting. Python is an object-orientated language, and as such it uses classes to define data types, including its primitive types.

Casting in python is therefore done using constructor functions:

• int() - constructs an integer number from an integer literal, a float literal (by rounding down to the previous whole number), or a string literal (providing the string represents a whole number)
• float() - constructs a float number from an integer literal, a float literal or a string literal (providing the string represents a float or an integer)
• str() - constructs a string from a wide variety of data types, including strings, integer literals and float literals

Example

Integers:

x = int(1)  # x will be 1

y = int(2.8) # y will be 2

z = int("3") # z will be 3

Example

Floats:

x = float(1)    # x will be 1.0

y = float(2.8)  # y will be 2.8

z = float("3")  # z will be 3.0

w = float("4.2") # w will be 4.2

Example

Strings:

x = str("s1") # x will be 's1'

y = str(2)   # y will be '2'

z = str(3.0) # z will be '3.0'