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

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

其他回答

我有这样的情况,我必须检查一个ID是否包含在另一个脚本/命令生成的ID列表中。 我的工作如下:

# the ID I was looking for
ID=1

# somehow generated list of IDs
LIST=$( <some script that generates lines with IDs> )
# list is curiously concatenated with a single space character
LIST=" $LIST "

# grep for exact match, boundaries are marked as space
# would therefore not reliably work for values containing a space
# return the count with "-c"
ISIN=$(echo $LIST | grep -F " $ID " -c)

# do your check (e. g. 0 for nothing found, everything greater than 0 means found)
if [ ISIN -eq 0 ]; then
    echo "not found"
fi
# etc.

你也可以像这样缩短/压缩它:

if [ $(echo " $( <script call> ) " | grep -F " $ID " -c) -eq 0 ]; then
    echo "not found"
fi

在我的例子中,我正在运行jq来过滤一些JSON的ID列表,然后必须检查我的ID是否在这个列表中,这对我来说是最好的。 它不适用于手动创建的LIST=("1" "2" "4")类型的数组,而是用于换行分隔的脚本输出。


附言:不能评论一个答案,因为我是相对较新的…

这种方法的优点是不需要遍历所有元素(至少不是显式地)。但是由于array.c中的array_to_string_internal()仍然循环遍历数组元素并将它们连接到一个字符串中,因此它可能并不比所提出的循环解决方案更有效,但它更具可读性。

if [[ " ${array[*]} " =~ " ${value} " ]]; then
    # whatever you want to do when array contains value
fi

if [[ ! " ${array[*]} " =~ " ${value} " ]]; then
    # whatever you want to do when array doesn't contain value
fi

请注意,如果您正在搜索的值是带有空格的数组元素中的某个单词,则会给出假阳性。例如

array=("Jack Brown")
value="Jack"

正则表达式将“Jack”视为在数组中,即使它不在数组中。所以你必须改变IFS和正则表达式上的分隔符如果你仍然想使用这个解决方案,就像这样

IFS="|"
array=("Jack Brown${IFS}Jack Smith")
value="Jack"

if [[ "${IFS}${array[*]}${IFS}" =~ "${IFS}${value}${IFS}" ]]; then
    echo "true"
else
    echo "false"
fi

unset IFS # or set back to original IFS if previously set

这将打印“false”。

显然,这也可以用作测试语句,允许将其表示为一行程序

[[ " ${array[*]} " =~ " ${value} " ]] && echo "true" || echo "false"

@ghostdog74关于使用大小写逻辑检查数组包含特定值的回答的一个小补充:

myarray=(one two three)
word=two
case "${myarray[@]}" in  ("$word "*|*" $word "*|*" $word") echo "found" ;; esac

或者打开extglob选项,你可以这样做:

myarray=(one two three)
word=two
shopt -s extglob
case "${myarray[@]}" in ?(*" ")"$word"?(" "*)) echo "found" ;; esac

我们也可以用if语句:

myarray=(one two three)
word=two
if [[ $(printf "_[%s]_" "${myarray[@]}") =~ .*_\[$word\]_.* ]]; then echo "found"; fi

别胡闹了!使您的解决方案简单、干净和可重用。

这些函数负责索引数组和关联数组。可以通过将搜索算法从线性搜索升级为二进制搜索(用于大型数据集)来改进它们。

##
# Determines if a value exists in an array.
###
function hasArrayValue ()
{
    local -r needle="{$1:?}"
    local -nr haystack="{$2:?}"  # Where you pass by reference to get the entire array in one argument.

    # Linear search. Upgrade to binary search for large datasets.
    for value in "${haystack[@]}"; do
        if [[ "$value" == "$needle" ]]; then
            return 0
        fi
    done

    return 1
}

##
# Determines if a value exists in an associative array / map.
###
function hasMapValue ()
{
    local -r needle="{$1:?}"
    local -nr haystack="{$2:?}"

    # Linear search. Upgrade to binary search for large datasets.
    for value in "${haystack[@]}"; do
        if [[ $value == $needle ]]; then
            return 0
        fi
    done

    return 1
}

是的,同样的逻辑,但在处理bash时,如果函数的名称可以让您知道迭代的对象(或不迭代的对象),则可能(可能)有用。

保持简单:

Array1=( "item1" "item2" "item3" "item-4" )
var="item3"

count=$(echo ${Array1[@]} | tr ' ' '\n' | awk '$1 == "'"$var"'"{print $0}' | wc -l)
[ $count -eq 0 ] && echo "Not found" || echo "found"