bash: find string in multiple other strings

Question

I'm trying to use bash to find if a short string is present in any string "sets". For example,

FRUIT="apple banana kiwi melon"
VEGETABLE="radish lettuce potato"
COLOR="blue red yellow green brown"

MY_CHOICE="kiwi"
MY_CHOICE_GROUP="?"

How can I set MY_CHOICE_GROUP to FRUIT?

I tried to use this StackOverflow solution, but it only works with a single string set.

Originally, I was using arrays to store the options in a set, but given the way bash handles iteration over arrays, it seems a string search would be more efficient.

Many thanks!

Answer 1

1. The simplest way, IMO, would be to just hardcode a bunch of case...esac labels.

   #!/bin/bash
   function lookup()
   {
       case "$1" in
           apple|banana|kiwi|melon)
               echo "FRUIT"
               ;;
   
           radish|lettuce|potato)  
               echo "VEGETABLE"
               ;;
   
           blue|red|yellow|green|brown)   
               echo "COLOR"
               ;;
       esac
   }
   
   MY_CHOICE="kiwi"
   MY_CHOICE_GROUP=$(lookup "$MY_CHOICE")
   
   echo $MY_CHOICE: $MY_CHOICE_GROUP
   

   See it live on ideone

2. Otherwise, consider associative arrays, see it live on ideone:

   #!/bin/bash
   declare -A groups
   
   groups["apple"]="FRUIT"
   groups["banana"]="FRUIT"
   groups["kiwi"]="FRUIT"
   groups["melon"]="FRUIT"
   
   groups["radish"]="VEGETABLE"
   groups["lettuce"]="VEGETABLE"
   groups["potato"]="VEGETABLE"
   
   groups["blue"]="COLOR"
   groups["red"]="COLOR"
   groups["yellow"]="COLOR"
   groups["green"]="COLOR"
   groups["brown"]="COLOR"
   
   MY_CHOICE="kiwi"
   MY_CHOICE_GROUP=${groups[$MY_CHOICE]}
   
   echo $MY_CHOICE: $MY_CHOICE_GROUP
   

Answer 2

Only shortening a bit @sehe's answer:

#!/bin/bash

declare -A groups
mkaso() { val="$1"; shift; for key in "$@"; do groups["$key"]="$val"; done; }

mkaso FRUIT apple banana kiwi melon
mkaso VEGETABLE radish lettuce potato
mkaso COLOR blue red yellow green brown
#declare -p groups

MY_CHOICE="kiwi"
MY_CHOICE_GROUP=${groups[$MY_CHOICE]}
echo $MY_CHOICE: $MY_CHOICE_GROUP