function in_list {
    SEARCH="$1"; shift
    LIST=( "$@" )
    if [ -z "${LIST}" ] || [ -z "${SEARCH}" ]; then
      return 1
    fi
    for ITEM in ${LIST[@]}; do
        if [[ "${ITEM}" == "${SEARCH}" ]]; then
            return 0
        fi
    done
    return 1
}

LIST=( "foo" "bar" "with space" "fiz" "buz" )

if (in_list "bar" "${LIST[@]}"); then
    echo "bar is in MY_LIST"
fi

bar is in MY_LIST