23

In zsh, I want to iterate over an associative array. I need both keys and values. But when I iterate over the associative array normally (for x in $assoc_array), I get only values.

All examples I've looked at show that, given a key, you can get its value from an associative array. My problem is getting the set of keys to begin with.

Does zsh support iterating over keys in an associative array?

  • If you have just a small list this might be an option: for i in a,b c_s,d ; do KEY=${i%,*}; VAL=${i#*,}; echo $KEY" XX "$VAL; done – math May 16 '14 at 14:44
12

You can get both keys and values at once with this nifty parameter expansion:

for key val in ${(kv)assoc_array}; do
    echo "$key -> $val"
done

See Parameter Expansion Flags in the Zsh manual.

  • This is way simpler +1 – TimSum Sep 12 '17 at 5:53
  • This doesn't work when the keys or values have spaces in them – Max Coplan Sep 9 at 1:33
30

I continued searching after asking my question and found this answer on the Unix StackExchange:

typeset -A assoc_array
assoc_array=(k1 v1 k2 v2 k3 v3)

for k in "${(@k)assoc_array}"; do
  echo "$k -> $assoc_array[$k]"
done

Output is:

k1 -> v1
k2 -> v2
k3 -> v3
  • 1
    For anyone wanting to test this in a useful way, try with the builtin $options. (See man zshoptions) – mVChr Oct 29 '16 at 9:29
  • What if the key is not an increasing number like foo, bar, etc like arr[foo]=baz? – Timo Dec 17 '17 at 20:28

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