Check if a Bash array contains a value

Question

In Bash, what is the simplest way to test if an array contains a certain value?

Answer 1

I generally write these kind of utilities to operate on the name of the variable, rather than the variable value, primarily because bash can't otherwise pass variables by reference.

Here's a version that works with the name of the array:

function array_contains # array value
{
    [[ -n "$1" && -n "$2" ]] || {
        echo "usage: array_contains  "
        echo "Returns 0 if array contains value, 1 otherwise"
        return 2
    }

    eval 'local values=("${'$1'[@]}")'

    local element
    for element in "${values[@]}"; do
        [[ "$element" == "$2" ]] && return 0
    done
    return 1
}

With this, the question example becomes:

array_contains A "one" && echo "contains one"

etc.