How to use arrays in Zsh

Zsh arrays keep ordered lists inside scripts and interactive functions, so a script can work through targets, arguments, file names, or option values without repeating a separate variable for each item.

Normal Zsh arrays use index 1 for the first element unless the script enables KSH_ARRAYS, and negative indexes count backward from the end. Values are assigned inside parentheses, appended with array+=(value), and expanded one element at a time with syntax such as ${array[1]}.

The example below builds a deployment target list, appends one more target, then prints the first item, last item, total count, and loop output. One target contains a space so the quoted loop proves each array element stays intact, and the sample uses a regular script array rather than the tied path array that controls PATH.

1. Create a script with an indexed Zsh array.

   deploy-targets.zsh

   #!/usr/bin/env zsh
   set -e
    
   targets=(web01 "db primary" cache01)
   targets+=(backup01)
    
   print -r -- "first=${targets[1]}"
   print -r -- "last=${targets[-1]}"
   print -r -- "count=${#targets[@]}"
   print -r -- "targets:"
   for target in "${targets[@]}"; do
       print -r -- "- $target"
   done

   Default Zsh arrays start at index 1. The ${targets[-1]} expansion reads the last element, and ${#targets[@]} returns the number of elements.

2. Check the script syntax before running it.

   $ zsh -n deploy-targets.zsh

   No output from zsh -n means Zsh parsed the script without finding a syntax error.

3. Run the script and confirm the array order.

   $ zsh deploy-targets.zsh
   first=web01
   last=backup01
   count=4
   targets:
   - web01
   - db primary
   - cache01
   - backup01

4. Keep array expansions quoted when elements might contain spaces.

   for target in "${targets[@]}"; do
       print -r -- "- $target"
   done

   Unquoted array expansion can split elements that contain spaces or glob characters. Quote ${array[@]} unless the script intentionally wants shell splitting.

5. Remove the sample script after testing.

   $ rm -f deploy-targets.zsh