Atom - Ḣ - Head (First)

Characters: Ḣ

Tags: array

Arity: monadic

This atom is monadic, which means it takes one argument.

Functionality

Pop and return the first element of a list (modifies the list).

Details

If the list is empty, returns zero. This mutates the original object itself, so 1,2,3 Ḣ,⁸Ɗ yields [1, [2, 3]], not [1, [1, 2, 3]]. If you do not want to modify the list, you can access the first element using 1ị$; however, a clever trick you can employ is ḷ/ (as long as your list isn't empty). This is technically less efficient because you reduce the whole list whereas random access is constant, but can save you a byte over 1ị$ if you would need the $ to group those links.