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 removing all decimals), 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
Output:
1
2
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
Output:
1.0
2.8
3.0
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’
Output:
s1
2
3.0