${(k)…}: Substitute array keys

For associative arrays, (k) substitutes array keys instead of values.

With subscripts, e.g. ${(k)array[value]}, it substitutes keys for associate arrays or indices for ordinary, indexed arrays.

Links

• Zsh manual on parameter expansion flags

Examples

Print keys of an associative array

1 2	declare -A data=([Joe]=4 [William]=3, [Jack]=2 [Averell]=1 ) echo "Dalton brothers: ${(k)data}"

Output:

1	Dalton brothers: William Joe Jack Averell