Check if an array contains a value

zsh doesn't have a way to check if a value is in an array, but can tell us (using ${(ie)}) the index of the element.

The i means inverse subscript, meaning that instead of accessing a value by its index, we want to access the index by its value.

e is for exact match; without it zsh will return the index of any value that contains the substring, instead of exactly matching it.

The trick is that if the value is not found, zsh will return the length of the array + 1.

So, to summarize, to check if the value zsh is in the array myArray, you would test it that way:

if [[ ${myArray[(ie)zsh]} -lt ${#myArray} ]]; then
  # ${#myArray} return the length of the array

Alternatively, if the string you're looking for is dynamic ($myVar), you'll need one more wrapping level: ${myArray[(ie)${myVar}]}.

Tags : #zsh

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