没有'grep'和循环的一行检查

if ( dlm=$'\x1F' ; IFS="$dlm" ; [[ "$dlm${array[*]}$dlm" == *"$dlm${item}$dlm"* ]] ) ; then
  echo "array contains '$item'"
else
  echo "array does not contain '$item'"
fi

这种方法既不使用grep这样的外部实用程序，也不使用循环。

这里发生的是:

we use a wildcard substring matcher to find our item in the array that is concatenated into a string; we cut off possible false positives by enclosing our search item between a pair of delimiters; we use a non-printable character as delimiter, to be on the safe side; we achieve our delimiter being used for array concatenation too by temporary replacement of the IFS variable value; we make this IFS value replacement temporary by evaluating our conditional expression in a sub-shell (inside a pair of parentheses)

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)

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…

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

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

The answer with most votes is very concise and clean, but it can have false positives when a space is part of one of the array elements. This can be overcome when changing IFS and using "${array[*]}" instead of "${array[@]}". The method is identical, but it looks less clean. By using "${array[*]}", we print all elements of $array, separated by the first character in IFS. So by choosing a correct IFS, you can overcome this particular issue. In this particular case, we decide to set IFS to an uncommon character $'\001' which stands for Start of Heading (SOH)

$ array=("foo bar" "baz" "qux")
$ IFS=$'\001'
$ [[ "$IFS${array[*]}$IFS" =~ "${IFS}foo${IFS}" ]] && echo yes || echo no
no
$ [[ "$IFS${array[*]}$IFS" =~ "${IFS}foo bar${IFS}" ]] && echo yes || echo no
yes
$ unset IFS

这解决了大多数假阳性问题，但需要一个好的IFS选择。

注意:如果之前设置了IFS，最好保存并重新设置，而不是使用未设置的IFS

相关:

访问bash命令行参数$@ vs $*