Check if a Bash array contains a value

Question

In Bash, what is the simplest way to test if an array contains a certain value?

Answer 1

I had the case that I had to check if an ID was contained in a list of IDs generated by another script / command. For me worked the following:

# the ID I was looking for
ID=1

# somehow generated list of IDs
LIST=$(  )
# 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.

You could also shorten / compact it like this:

if [ $(echo " $(