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 array should then be discarded and i want to assign the temp array to the original array variable.

Sudo code:

declare -A MAINARRAY
declare -A TEMPARRAY
... populate ${MAINARRAY[...]} ...

while something; do     #Drain some values from MAINARRAY to TEMPARRAY
    ${TEMPARRAY["$name"]}=((${MAINARRAY["$name"]} + $somevalue))
done
... other manipulations to TEMPARRAY ...

unset MAINARRAY        #discard left over values that had no update
declare -A MAINARRAY
MAINARRAY=${TEMPARRAY[@]}  #assign updated TEMPARRAY back to MAINARRAY (ERROR HERE)

Answer 1

Here is a small Copy-Function for bash-Variables of any kind
- normal scalar variables
- indexed arrays
- associative arrays

### Function vcp    -VariableCoPy-  
# $1 Name of existing Source-Variable  
# $2 Name for the Copy-Target  
vcp() {
    local var=$(declare -p $1)
    var=${var/declare /declare -g }
    eval "${var/$1=/$2=}"
}

Usage, Examples:

# declarations
var="  345  89  "
ind_array=(Betty "  345  89  ")
declare -A asso_array=([one]=Harry [two]=Betty [some_signs]=" +*.<\$~,'/ ")  

# produce the copy
vcp var varcopy
vcp ind_array ind_array_copied
vcp asso_array asso_array_2   

# now you can check the equality between original and copy with commands like
# declare -p <name>

The results

--3    1: "${asso_array[@]}"   
(5)       asso_array[one]:        |Harry|   
(11)      asso_array[some_signs]: | +*.<$~,'/ |   
(5)       asso_array[two]:        |Betty|   
--3    4: "${asso_array_2[@]}"   
(5)       asso_array_2[one]:        |Harry|   
(11)      asso_array_2[some_signs]: | +*.<$~,'/ |   
(5)       asso_array_2[two]:        |Betty|   
--2    7: "${ind_array[@]}"   
(5)       ind_array[0]:   |Betty|   
(11)      ind_array[1]:   |  345  89  |   
--2    9: "${ind_array_copied[@]}"   
(5)       ind_array_copied[0]:   |Betty|   
(11)      ind_array_copied[1]:   |  345  89  |   
(11)  11: "$var":   |  345  89  |  
(11)  12: "$varcopy":   |  345  89  |  

Answer 2

This one-liner does an associative array copy: MAINARRAY=TEMPARRAY

eval $(typeset -A -p TEMPARRAY|sed 's/ TEMPARRAY=/ MAINARRAY=/')