One of the new features in Bash v4 are the associative arrays using strings as index instead numbers
here a small example of use
#!/bin/bash
declare -A myArray #declare array
myArray[cat]=gato #attach a value into index cat
myArray[dog]=can #attach a value into index dog
creature="fish" #declare a variable
myArray[$creature]=peixe #attach a value into index fish
#get all array values
for key in "${!myArray[@]}"
do
echo "index value=$key content value= ${myArray[$key]}"
done