虽然这里有几个很好的和有用的答案，但我没有找到一个似乎是性能、跨平台和健壮性的正确组合;所以我想分享一下我为我的代码编写的解决方案:

#!/bin/bash

# array_contains "$needle" "${haystack[@]}"
#
# Returns 0 if an item ($1) is contained in an array ($@).
#
# Developer note:
#    The use of a delimiter here leaves something to be desired. The ideal
#    method seems to be to use `grep` with --line-regexp and --null-data, but
#    Mac/BSD grep doesn't support --line-regexp.
function array_contains()
{
    # Extract and remove the needle from $@.
    local needle="$1"
    shift

    # Separates strings in the array for matching. Must be extremely-unlikely
    # to appear in the input array or the needle.
    local delimiter='#!-\8/-!#'

    # Create a string with containing every (delimited) element in the array,
    # and search it for the needle with grep in fixed-string mode.
    if printf "${delimiter}%s${delimiter}" "$@" | \
        grep --fixed-strings --quiet "${delimiter}${needle}${delimiter}"; then
        return 0
    fi

    return 1
}

如何检查一个Bash数组是否包含一个值

假阳性匹配

array=(a1 b1 c1 d1 ee)

[[ ${array[*]} =~ 'a' ]] && echo 'yes' || echo 'no'
# output:
yes

[[ ${array[*]} =~ 'a1' ]] && echo 'yes' || echo 'no'
# output:
yes

[[ ${array[*]} =~ 'e' ]] && echo 'yes' || echo 'no'
# output:
yes

[[ ${array[*]} =~ 'ee' ]] && echo 'yes' || echo 'no'
# output:
yes

精确匹配

为了寻找精确匹配，你的正则表达式模式需要在值的前后添加额外的空格，如(^|[[:space:]])" value "($|[[:space:]])

# Exact match

array=(aa1 bc1 ac1 ed1 aee)

if [[ ${array[*]} =~ (^|[[:space:]])"a"($|[[:space:]]) ]]; then
    echo "Yes";
else
    echo "No";
fi
# output:
No

if [[ ${array[*]} =~ (^|[[:space:]])"ac1"($|[[:space:]]) ]]; then
    echo "Yes";
else
    echo "No";
fi
# output:
Yes

find="ac1"
if [[ ${array[*]} =~ (^|[[:space:]])"$find"($|[[:space:]]) ]]; then
    echo "Yes";
else
    echo "No";
fi
# output:
Yes

有关更多用法示例，示例的来源在这里

使用参数展开:

如果参数为空或未设置，则什么都没有 替换，否则词的展开就会被替换。

declare -A myarray
myarray[hello]="world"

for i in hello goodbye 123
do
  if [ ${myarray[$i]:+_} ]
  then
    echo ${!myarray[$i]} ${myarray[$i]} 
  else
    printf "there is no %s\n" $i
  fi
done

OP自己添加了以下答案，并附上了评论:

在回答和评论的帮助下，经过一些测试，我得出了这个结论:

function contains() {
    local n=$#
    local value=${!n}
    for ((i=1;i < $#;i++)) {
        if [ "${!i}" == "${value}" ]; then
            echo "y"
            return 0
        fi
    }
    echo "n"
    return 1
}

A=("one" "two" "three four")
if [ $(contains "${A[@]}" "one") == "y" ]; then
    echo "contains one"
fi
if [ $(contains "${A[@]}" "three") == "y" ]; then
    echo "contains three"
fi

下面是实现这一点的一个小函数。搜索字符串是第一个参数，其余是数组元素:

set +e #otherwise the script will exit on error
containsElement () {
  local e match="$1"
  shift
  for e; do [[ "$e" == "$match" ]] && return 0; done
  return 1
}

该函数的测试运行如下:

$ array=("something to search for" "a string" "test2000")
$ containsElement "a string" "${array[@]}"
$ echo $?
0
$ containsElement "blaha" "${array[@]}"
$ echo $?
1

以下是几个可能实现的编译，包括集成验证和简单的基准测试(需要Bash >= 4.0):

#!/usr/bin/env bash

# Check if array contains item [$1: item, $2: array name]
function in_array_1() {
    local needle="$1" item
    local -n arrref="$2"
    for item in "${arrref[@]}"; do
        [[ "${item}" == "${needle}" ]] && return 0
    done
    return 1
}

# Check if array contains item [$1: item, $2: array name]
function in_array_2() {
    local needle="$1" arrref="$2[@]" item
    for item in "${!arrref}"; do
        [[ "${item}" == "${needle}" ]] && return 0
    done
    return 1
}

# Check if array contains item [$1: item, $2: array name]
function in_array_3() {
    local needle="$1" i
    local -n arrref="$2"
    for ((i=0; i < ${#arrref[@]}; i++)); do
        [[ "${arrref[i]}" == "${needle}" ]] && return 0
    done
    return 1
}

# Check if array contains item [$1: item, $2..$n: array items]
function in_array_4() {
    local needle="$1" item
    shift
    for item; do
        [[ "${item}" == "${needle}" ]] && return 0
    done
    return 1
}

# Check if array contains item [$1: item, $2..$n: array items]
function in_array_5() {
    local needle="$1" item
    for item in "${@:2}"; do
        [[ "${item}" == "${needle}" ]] && return 0
    done
    return 1
}

# Check if array contains item [$1: item, $2: array name]
function in_array_6() {
    local needle="$1" arrref="$2[@]" array i
    array=("${!arrref}")
    for ((i=0; i < ${#array[@]}; i++)); do
        [[ "${array[i]}" == "${needle}" ]] && return 0
    done
    return 1
}

# Check if array contains item [$1: item, $2..$n: array items]
function in_array_7() {
    local needle="$1" array=("${@:2}") item
    for item in "${array[@]}"; do
        [[ "${item}" == "${needle}" ]] && return 0
    done
    return 1
}

# Check if array contains item [$1: item, $2..$n: array items]
function in_array_8() {
    local needle="$1"
    shift
    while (( $# > 0 )); do
        [[ "$1" == "${needle}" ]] && return 0
        shift
    done
    return 1
}


#------------------------------------------------------------------------------


# Generate map for array [$1: name of source array, $2: name of target array]
# NOTE: target array must be pre-declared by caller using 'declare -A <name>'
function generate_array_map() {
    local -n srcarr="$1" dstmap="$2"
    local i key
    dstmap=()
    for i in "${!srcarr[@]}"; do
        key="${srcarr[i]}"
        [[ -z ${dstmap["${key}"]+set} ]] && dstmap["${key}"]=${i} || dstmap["${key}"]+=,${i}
    done
}

# Check if array contains item [$1: item, $2: name of array map]
function in_array_9() {
    local needle="$1"
    local -n mapref="$2"
    [[ -n "${mapref["${needle}"]+set}" ]] && return 0 || return 1
}


#------------------------------------------------------------------------------


# Test in_array function [$1: function name, $2: function description, $3: test array size]
function test() {
    local tname="$1" tdesc="$2" tn=$3 ti=0 tj=0 ta=() tct=0 tepapre="" tepapost="" tepadiff=()
    local -A tam=()

    echo -e "\e[1m${tname} (${tdesc}):\e[0m"

    # Generate list of currently defined variables
    tepapre="$(compgen -v)"

    # Fill array with random items
    for ((ti=0; ti < ${tn}; ti++)); do
        ta+=("${RANDOM} ${RANDOM} ${RANDOM} ${RANDOM}")
    done

    # Determine function call type (pass array items, pass array name, pass array map)
    case "${tname}" in
        "in_array_1"|"in_array_2"|"in_array_3"|"in_array_6") tct=0; ;;
        "in_array_4"|"in_array_5"|"in_array_7"|"in_array_8") tct=1; ;;
        "in_array_9") generate_array_map ta tam; tct=2; ;;
        *) echo "Unknown in_array function '${tname}', aborting"; return 1; ;;
    esac

    # Verify in_array function is working as expected by picking a few random
    # items and checking
    echo -e "\e[1mVerification...\e[0m"
    for ((ti=0; ti < 10; ti++)); do
        tj=$(( ${RANDOM} % ${#ta[@]} ))
        echo -n "Item ${tj} '${ta[tj]}': "
        if (( ${tct} == 0 )); then
            "${tname}" "${ta[tj]}" ta && echo -en "\e[1;32mok\e[0m" || echo -en "\e[1;31mnok\e[0m"
            echo -n " "
            "${tname}" "${ta[tj]}.x" ta && echo -en "\e[1;31mnok\e[0m" || echo -en "\e[1;32mok\e[0m"
        elif (( ${tct} == 1 )); then
            "${tname}" "${ta[tj]}" "${ta[@]}" && echo -en "\e[1;32mok\e[0m" || echo -en "\e[1;31mnok\e[0m"
            echo -n " "
            "${tname}" "${ta[tj]}.x" "${ta[@]}" && echo -en "\e[1;31mnok\e[0m" || echo -en "\e[1;32mok\e[0m"
        elif (( ${tct} == 2 )); then
            "${tname}" "${ta[tj]}" tam && echo -en "\e[1;32mok\e[0m" || echo -en "\e[1;31mnok\e[0m"
            echo -n " "
            "${tname}" "${ta[tj]}.x" tam && echo -en "\e[1;31mnok\e[0m" || echo -en "\e[1;32mok\e[0m"
        fi
        echo
    done

    # Benchmark in_array function
    echo -en "\e[1mBenchmark...\e[0m"
    time for ((ti=0; ti < ${#ta[@]}; ti++)); do
        if (( ${tct} == 0 )); then
            "${tname}" "${ta[ti]}" ta
        elif (( ${tct} == 1 )); then
            "${tname}" "${ta[ti]}" "${ta[@]}"
        elif (( ${tct} == 2 )); then
            "${tname}" "${ta[ti]}" tam
        fi
    done

    # Generate list of currently defined variables, compare to previously
    # generated list to determine possible environment pollution
    echo -e "\e[1mEPA test...\e[0m"
    tepapost="$(compgen -v)"
    readarray -t tepadiff < <(echo -e "${tepapre}\n${tepapost}" | sort | uniq -u)
    if (( ${#tepadiff[@]} == 0 )); then
        echo -e "\e[1;32mclean\e[0m"
    else
        echo -e "\e[1;31mpolluted:\e[0m ${tepadiff[@]}"
    fi

    echo
}


#------------------------------------------------------------------------------


# Test in_array functions
n=5000
echo
( test in_array_1 "pass array name, nameref reference, for-each-loop over array items" ${n} )
( test in_array_2 "pass array name, indirect reference, for-each-loop over array items" ${n} )
( test in_array_3 "pass array name, nameref reference, c-style for-loop over array items by index" ${n} )
( test in_array_4 "pass array items, for-each-loop over arguments" ${n} )
( test in_array_5 "pass array items, for-each-loop over arguments as array" ${n} )
( test in_array_6 "pass array name, indirect reference + array copy, c-style for-loop over array items by index" ${n} )
( test in_array_7 "pass array items, copy array from arguments as array, for-each-loop over array items" ${n} )
( test in_array_8 "pass array items, while-loop, shift over arguments" ${n} )
( test in_array_9 "pre-generated array map, pass array map name, direct test without loop" ${n} )

结果:

in_array_1 (pass array name, nameref reference, for-each-loop over array items):
Verification...
Item 862 '19528 10140 12669 17820': ok ok
Item 2250 '27262 30442 9295 24867': ok ok
Item 4794 '3857 17404 31925 27993': ok ok
Item 2532 '14553 12282 26511 32657': ok ok
Item 1911 '21715 8066 15277 27126': ok ok
Item 4289 '3081 10265 16686 19121': ok ok
Item 4837 '32220 1758 304 7871': ok ok
Item 901 '20652 23880 20634 14286': ok ok
Item 2488 '14578 8625 30251 9343': ok ok
Item 4165 '4514 25064 29301 7400': ok ok
Benchmark...
real    1m11,796s
user    1m11,262s
sys     0m0,473s
EPA test...
clean

in_array_2 (pass array name, indirect reference, for-each-loop over array items):
Verification...
Item 2933 '17482 25789 27710 2096': ok ok
Item 3584 '876 14586 20885 8567': ok ok
Item 872 '176 19749 27265 18038': ok ok
Item 595 '6597 31710 13266 8813': ok ok
Item 748 '569 9200 28914 11297': ok ok
Item 3791 '26477 13218 30172 31532': ok ok
Item 2900 '3059 8457 4879 16634': ok ok
Item 676 '23511 686 589 7265': ok ok
Item 2248 '31351 7961 17946 24782': ok ok
Item 511 '8484 23162 11050 426': ok ok
Benchmark...
real    1m11,524s
user    1m11,086s
sys     0m0,437s
EPA test...
clean

in_array_3 (pass array name, nameref reference, c-style for-loop over array items by index):
Verification...
Item 1589 '747 10250 20133 29230': ok ok
Item 488 '12827 18892 31996 1977': ok ok
Item 801 '19439 25243 24485 24435': ok ok
Item 2588 '17193 18893 21610 9302': ok ok
Item 4436 '7100 655 8847 3068': ok ok
Item 2620 '19444 6457 28835 24717': ok ok
Item 4398 '4420 16336 612 4255': ok ok
Item 2430 '32397 2402 12631 29774': ok ok
Item 3419 '906 5361 32752 7698': ok ok
Item 356 '9776 16485 20838 13330': ok ok
Benchmark...
real    1m17,037s
user    1m17,019s
sys     0m0,005s
EPA test...
clean

in_array_4 (pass array items, for-each-loop over arguments):
Verification...
Item 1388 '7932 15114 4025 15625': ok ok
Item 3900 '23863 25328 5632 2752': ok ok
Item 2678 '31296 4216 17485 8874': ok ok
Item 1893 '16952 29047 29104 23384': ok ok
Item 1616 '19543 5999 4485 22929': ok ok
Item 93 '14456 2806 12829 19552': ok ok
Item 265 '30961 19733 11863 3101': ok ok
Item 4615 '10431 9566 25767 13518': ok ok
Item 576 '11726 15104 11116 74': ok ok
Item 3829 '19371 25026 6252 29478': ok ok
Benchmark...
real    1m30,912s
user    1m30,740s
sys     0m0,011s
EPA test...
clean

in_array_5 (pass array items, for-each-loop over arguments as array):
Verification...
Item 1012 '29213 31971 21483 30225': ok ok
Item 2802 '4079 5423 29240 29619': ok ok
Item 473 '6968 798 23936 6852': ok ok
Item 2183 '20734 4521 30800 2126': ok ok
Item 3059 '14952 9918 15695 19309': ok ok
Item 1424 '25784 28380 14555 21893': ok ok
Item 1087 '16345 19823 26210 20083': ok ok
Item 257 '28890 5198 7251 3866': ok ok
Item 3986 '29035 19288 12107 3857': ok ok
Item 2509 '9219 32484 12842 27472': ok ok
Benchmark...
real    1m53,485s
user    1m53,404s
sys     0m0,077s
EPA test...
clean

in_array_6 (pass array name, indirect reference + array copy, c-style for-loop over array items by index):
Verification...
Item 4691 '25498 10521 20673 14948': ok ok
Item 263 '25265 29824 3876 14088': ok ok
Item 2550 '2416 14274 12594 29740': ok ok
Item 2269 '2769 11436 3622 28273': ok ok
Item 3246 '23730 25956 3514 17626': ok ok
Item 1059 '10776 12514 27222 15640': ok ok
Item 53 '23813 13365 16022 4092': ok ok
Item 1503 '6593 23540 10256 17818': ok ok
Item 2452 '12600 27404 30960 26759': ok ok
Item 2526 '21190 32512 23651 7865': ok ok
Benchmark...
real    1m54,793s
user    1m54,326s
sys     0m0,457s
EPA test...
clean

in_array_7 (pass array items, copy array from arguments as array, for-each-loop over array items):
Verification...
Item 2212 '12127 12828 27570 7051': ok ok
Item 1393 '19552 26263 1067 23332': ok ok
Item 506 '18818 8253 14924 30710': ok ok
Item 789 '9803 1886 17584 32686': ok ok
Item 1795 '19788 27842 28044 3436': ok ok
Item 376 '4372 16953 17280 4031': ok ok
Item 4846 '19130 6261 21959 6869': ok ok
Item 2064 '2357 32221 22682 5814': ok ok
Item 4866 '10928 10632 19175 14984': ok ok
Item 1294 '8499 11885 5900 6765': ok ok
Benchmark...
real    2m35,012s
user    2m33,578s
sys     0m1,433s
EPA test...
clean

in_array_8 (pass array items, while-loop, shift over arguments):
Verification...
Item 134 '1418 24798 20169 9501': ok ok
Item 3986 '12160 12021 29794 29236': ok ok
Item 1607 '26633 14260 18227 898': ok ok
Item 2688 '18387 6285 2385 18432': ok ok
Item 603 '1421 306 6102 28735': ok ok
Item 625 '4530 19718 30900 1938': ok ok
Item 4033 '9968 24093 25080 8179': ok ok
Item 310 '6867 9884 31231 29173': ok ok
Item 661 '3794 4745 26066 22691': ok ok
Item 4129 '3039 31766 6714 4921': ok ok
Benchmark...
real    5m51,097s
user    5m50,566s
sys     0m0,495s
EPA test...
clean

in_array_9 (pre-generated array map, pass array map name, direct test without loop):
Verification...
Item 3696 '661 6048 13881 26901': ok ok
Item 815 '29729 13733 3935 20697': ok ok
Item 1076 '9220 3405 18448 7240': ok ok
Item 595 '8912 2886 13678 24066': ok ok
Item 2803 '13534 23891 5344 652': ok ok
Item 1810 '12528 32150 7050 1254': ok ok
Item 4055 '21840 7436 1350 15443': ok ok
Item 2416 '19550 28434 17110 31203': ok ok
Item 1630 '21054 2819 7527 953': ok ok
Item 1044 '30152 22211 22226 6950': ok ok
Benchmark...
real    0m0,128s
user    0m0,128s
sys     0m0,000s
EPA test...
clean