What does the “||=” operand stand for in ruby [duplicate]

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It is the shorthand for a logical OR operation. It is equivalent to:

a || a = b

Note: The above code sample has been corrected to reflect the true (if unintuitive) behavior if expanding a ||= b. Thanks to the people who pointed that out for me. Here is the source

if a evaluates to true it will remain as is, otherwise b will be assigned to a. In ruby nil evaluates to false, so you can see how this is useful for lazy loading and default value assignment.

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