Course of Raku / Advanced / Subroutines / Anonymous subroutines / Exercises / An anonymous square

Solution: An anonymous square

Here is a possible solution to the task.

Code

say (1, 2, 3).map(sub ($x) { $x * $x });

🦋 You can find the source code in the file anonymous-square.raku.

Output

(1 4 9)

Comments

1. The sub ($x) { $x * $x } has no name and is never stored in a variable — it is handed straight to map as its argument.

2. map applies it to each element of 1, 2, 3, squaring them into (1 4 9). Passing an anonymous subroutine inline like this is the most common reason to write one.

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