Representing Absence

Sometimes the honest answer is there is no value here. A user skipped their middle name. A search found no match. A function did its job and has nothing to hand back.

Programming needs a way to say nothing, and it's genuinely different from zero, from an empty string, and from false. Zero is a number. An empty string is text with no characters. Nothing is the absence of any value at all.

Intentional absence

PYTHON

middle_name = None

JAVASCRIPT

let middleName = null;

Compare → Python's None and JavaScript's null both mean the same thing: a deliberate, programmer-chosen 'there is no value here.' This is a SIMILAR CONCEPT: near-perfect equivalents you can translate between freely.

EXAMPLE

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YOUR TURN

Your turn → Create a variable for a phone number that hasn't been given yet, set it to None (null in JavaScript), and print it and its type.

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Syntax has to be exact. Every quote, bracket and parenthesis needs its partner, and in Python the spaces at the start of a line count. One slip and the program won't run; the message will say where.

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