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Python Specify Variable Type


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
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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
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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'
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