How to rename an associative array in Bash?

Question

I need to loop over an associative array and drain the contents of it to a temp array (and perform some update to the value).

The leftover contents of the first arra

Answer 1

expanding on Luca Borrione's cp_hash - which didn't work for me, and I gave up trying to track down the eval expansion issue - I ran into differences before and after bash 4.2. after 4.2(something) this gets a lot easier... but that's not backwards compatible. See 1 and 2

so my variation tested on 4.1.2(1) and 4.3.46(1):

#!/bin/bash
## bash4 due to associative arrays!

    function cp_hash() {
        ## REQUIRES you to declare -A $2 in advance.
        local original_hash_name="$1"
        local copy_hash_name="$2"
        #
        # sadly we have no way to identify if you have already declared it, so bull ahead.
        #
        ## store the definition of the old array
        local __copy__=$(declare -p $original_hash_name)
        ## rename the array inside the definition
        __copy__=${__copy__/${original_hash_name}=/__copy__=}

        ## for bash 4.2 > we could end here.
        ## declare -A creates local scope variables by default, so add -g
        ## this DOES NOT work prior to 4.2, even w/o -g and w/ a declare outside.
        #    __copy__=${__copy__/${original_hash_name}=/${copy_hash_name}=}
        #    eval ${__copy__/-A/-g -A}

        ## for bash4 where we can't do -g, then:
        ## local associative array based on the definition we stored and modified
        eval ${__copy__}
        ## loop through the local copy, and store it in the declared-outside copy.
        for i in "${!__copy__[@]}"
        do
            eval ${copy_hash_name}[$i]=${__copy__[$i]}
        done
    }

    declare -A hash
    hash[hello]=world
    hash[ab]=cd

    #not required for 4.2+ if you use -g, neither helps nor hinders
    declare -A copy

    cp_hash 'hash' 'copy'

    echo hash: ${hash[@]}
    echo copy: ${copy[@]}

    echo "copy result loop"
    for i in "${!copy[@]}"
    do
        echo "key  : $i | value: ${copy[$i]}"
    done