Parallel assignment

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In Ruby, what is the idiomatic way to swap the values of two variables in a single line?

The correct answer is

a, b = b, a

temp = a; a = b; b = temp

a.swap(b)

a ^ b ^ a

In Ruby, the assignment statement allows you to simultaneously assign values to multiple variables.

The expression a, b = b, a takes advantage of this feature to swap the values of variables a and b in a single line.

Here's how it works:

The right-hand side, b, a, creates a temporary array with the values of b and a.
The left-hand side, a, b, then destructively assigns these values back to a and b, effectively swapping their values.

This approach is concise, readable, and considered idiomatic in Ruby for swapping variable values.

It eliminates the need for a temporary variable and is a common and elegant pattern in the language.

Voilà!