Check if an element is present in a Bash array [duplicate]

Answer 1

1) Initialize array arr and add elements

2) set variable to search for SEARCH_STRING

3) check if your array contains element

arr=()
arr+=('a')
arr+=('b')
arr+=('c')

SEARCH_STRING='b'

if [[ " ${arr[*]} " == *"$SEARCH_STRING"* ]];
then
    echo "YES, your arr contains $SEARCH_STRING"
else
    echo "NO, your arr does not contain $SEARCH_STRING"
fi

Answer 2

As bash does not have a built-in value in array operator and the =~ operator or the [[ "${array[@]" == *"${item}"* ]] notation keep confusing me, I usually combine grep with a here-string:

colors=('black' 'blue' 'light green')
if grep -q 'black' <<< "${colors[@]}"
then
    echo 'match'
fi

Beware however that this suffers from the same false positives issue as many of the other answers that occurs when the item to search for is fully contained, but is not equal to another item:

if grep -q 'green' <<< "${colors[@]}"
then
    echo 'should not match, but does'
fi

If that is an issue for your use case, you probably won't get around looping over the array:

for color in "${colors[@]}"
do
    if [ "${color}" = 'green' ]
    then
        echo "should not match and won't"
        break
    fi
done

for color in "${colors[@]}"
do
    if [ "${color}" = 'light green' ]
    then
        echo 'match'
        break
    fi
done