在Bash中,测试数组是否包含某个值的最简单方法是什么?


当前回答

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)

其他回答

for i in "${array[@]}"
do
    if [ "$i" -eq "$yourValue" ] ; then
        echo "Found"
    fi
done

字符串:

for i in "${array[@]}"
do
    if [ "$i" == "$yourValue" ] ; then
        echo "Found"
    fi
done

使用grep和printf

在新行上格式化每个数组成员,然后grep这些行。

if printf '%s\n' "${array[@]}" | grep -x -q "search string"; then echo true; else echo false; fi
example:
$ array=("word", "two words")
$ if printf '%s\n' "${array[@]}" | grep -x -q "two words"; then echo true; else echo false; fi
true

注意,这对delimeter和空格没有问题。

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
}

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

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