Joining an array in Bash (like " ".join() in Python)

array_join.sh

function array_join() {
    # Join an array with a a separator character.
    # WARNING: This only works in bash.  You should also pass the array by
    #          reference.  Example:
    #          my_array=( "one" "two" "three")
    #          joined=$( array_join my_array "|")
    local -n arr=$1
    local sep=${2:-" "}
    printf -v result "%s${sep}" "${arr[@]}"

    # strip the last separator character
    printf "%s" "${result%?}"
}