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What is the := operator?

In some programming languages, I see (ex.):

x := y

What is this := operator generally called and what does it do?

Solution

  • In all languages that support an operator := it means assignment.

    • In languages that support an operator :=, the = operator usually means an equality comparison.
    • In languages where = means assignment, == is typically used for equality comparison.

    does := mean =?

    I can't recall any languages where := means the same as =.

    In MySQL := and = are both used for assignment, however they are not interchangeable and selecting the correct one depends on the context. To make matters more confusing the = operator is also used for comparison. The interpretation of = as either assignment or comparison also depends on context.