如果你需要性能，你不希望每次搜索时都要遍历整个数组。

在这种情况下，您可以创建一个表示该数组索引的关联数组(哈希表或字典)。也就是说，它将每个数组元素映射到它在数组中的索引:

make_index () {
  local index_name=$1
  shift
  local -a value_array=("$@")
  local i
  # -A means associative array, -g means create a global variable:
  declare -g -A ${index_name}
  for i in "${!value_array[@]}"; do
    eval ${index_name}["${value_array[$i]}"]=$i
  done
}

然后你可以这样使用它:

myarray=('a a' 'b b' 'c c')
make_index myarray_index "${myarray[@]}"

并像这样测试成员:

member="b b"
# the "|| echo NOT FOUND" below is needed if you're using "set -e"
test "${myarray_index[$member]}" && echo FOUND || echo NOT FOUND

或者:

if [ "${myarray_index[$member]}" ]; then 
  echo FOUND
fi

请注意，即使在测试值或数组值中存在空格，该解决方案也能正确执行。

作为奖励，您还可以通过以下方式获得数组中值的索引:

echo "<< ${myarray_index[$member]} >> is the index of $member"

如果您想做一个快速而复杂的测试，看看是否值得遍历整个数组以获得精确匹配，Bash可以像对待标量一样对待数组。测试标量中的匹配项，如果没有，则跳过循环节省时间。显然你会得到假阳性。

array=(word "two words" words)
if [[ ${array[@]} =~ words ]]
then
    echo "Checking"
    for element in "${array[@]}"
    do
        if [[ $element == "words" ]]
        then
            echo "Match"
        fi
    done
fi

这将输出“Checking”和“Match”。使用array=(word "two words" something)，它只会输出"Checking"。使用array=(单词“two widgets”什么的)将没有输出。

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
}

我通常只使用:

inarray=$(echo ${haystack[@]} | grep -o "needle" | wc -w)

非零值表示找到了匹配。

．.． 实际上，为了解决它不能与needle1和needle2工作的问题，如果你只想要一个精确匹配，没有更多，没有更少，只需在-o后面添加一个w标志，用于整个单词匹配:

inarray=$(echo ${haystack[@]} | grep -ow "needle" | wc -w)

扩展上面来自Sean DiSanti的答案，我认为下面是一个简单而优雅的解决方案，它避免了对数组进行循环，并且不会由于部分匹配而给出假阳性

function is_in_array {
    local ELEMENT="${1}"
    local DELIM=","
    printf "${DELIM}%s${DELIM}" "${@:2}" | grep -q "${DELIM}${ELEMENT}${DELIM}"
}

可以这样称呼:

$ haystack=("needle1" "needle2" "aneedle" "spaced needle")
$ is_in_array "needle" "${haystack[@]}"
$ echo $?
1
$ is_in_array "needle1" "${haystack[@]}"
$ echo $?
0

另一个没有函数的代码:

(for e in "${array[@]}"; do [[ "$e" == "searched_item" ]] && exit 0; done) && echo "found" || echo "not found"

谢谢@Qwerty关于空格的提示!

对应的功能:

find_in_array() {
  local word=$1
  shift
  for e in "$@"; do [[ "$e" == "$word" ]] && return 0; done
  return 1
}

例子:

some_words=( these are some words )
find_in_array word "${some_words[@]}" || echo "expected missing! since words != word"