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

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

其他回答

如果你不想重复,这是值得研究的:

#!/bin/bash
myarray=("one" "two" "three");
wanted="two"
if `echo ${myarray[@]/"$wanted"/"WAS_FOUND"} | grep -q "WAS_FOUND" ` ; then
 echo "Value was found"
fi
exit

片段改编自:http://www.thegeekstuff.com/2010/06/bash-array-tutorial/ 我认为这很聪明。

编辑: 你可以这样做:

if `echo ${myarray[@]} | grep -q "$wanted"` ; then
echo "Value was found"
fi

但后者仅在数组包含唯一值时有效。我认为,在143中寻找1只会给出假阳性。

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"

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

结合Beorn Harris和loentar的回答,我们得出了一个更有趣的单行测试:

delim=$'\x1F' # define a control code to be used as more or less reliable delimiter
if [[ "${delim}${array[@]}${delim}" =~ "${delim}a string to test${delim}" ]]; then
    echo "contains 'a string to test'"
fi

它不使用额外的函数,不替换测试,并添加了额外的保护,防止使用控制代码作为分隔符偶尔出现错误匹配。


UPD:感谢@ChrisCogdon的注意,这个错误的代码被重写并以https://stackoverflow.com/a/58527681/972463的形式发布。