id()

Published Jun 22, 2023
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The id() function gives a unique number for any object in Python. This number is the location of the object in the computer’s memory. This will be consistent for the duration of the object’s lifetime.

Syntax

id(object)

The parameter, object, can be any given object such as a string, list, number, dictionary, etc.

Example

In the example below, when two immutable variables are compared using the id() function, both return the same value pointing to the same location in memory.

This is because immutable objects don’t change. The following example uses an immutable string object to demonstrate this:

color = 'green'
favColor = 'green'
print(id(color))
print(id(favColor))

This example results in something resembling the following output:

140307997340656
140307997340656

Example 2

In this next example, the id() function will be executed with two mutable variables. Take note of how the function will return different values: two separate unique ids.

This is because mutable objects are able to change. A mutable list object can be used to demonstrate this:

animals = ['lions', 'tigers', 'bears']
favAnimals = ['lions', 'tigers', 'bears']
print(id(animals))
print(id(favAnimals))

This example results in something resembling the following output:

140279020355392
140279020204352

Codebyte Example

The following example displays the output of two immutable number objects:

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