How to pass an associative array as argument to a function in Bash?

arrays bash associative-array associative
niksfirefly picture niksfirefly · Nov 1, 2010 · Viewed 23.3k times · Source

How do you pass an associative array as an argument to a function? Is this possible in Bash?

The code below is not working as expected:

function iterateArray
{
    local ADATA="${@}"            # associative array

for key in "${!ADATA[@]}"
do
    echo "key - ${key}"
    echo "value: ${ADATA[$key]}"

done

}

Passing associative arrays to a function like normal arrays does not work:

iterateArray "$A_DATA"

or

iterateArray "$A_DATA[@]"

Answer

Florian Feldhaus picture Florian Feldhaus · Jan 16, 2012

I had exactly the same problem last week and thought about it for quite a while.

It seems, that associative arrays can't be serialized or copied. There's a good Bash FAQ entry to associative arrays which explains them in detail. The last section gave me the following idea which works for me:

function print_array {
    # eval string into a new associative array
    eval "declare -A func_assoc_array="${1#*=}
    # proof that array was successfully created
    declare -p func_assoc_array
}

# declare an associative array
declare -A assoc_array=(["key1"]="value1" ["key2"]="value2")
# show associative array definition
declare -p assoc_array

# pass associative array in string form to function
print_array "$(declare -p assoc_array)"

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