Bash Return Multiple Values from a Function using an Associative Array

Internal

• Bash Arrays | Associative Array Patterns
• Bash Functions | Function Patterns

Overview

If the name of the associative array must be passed as the argument of the method, use Option 1. Otherwise, if we assume a known associative array set by the calling layer, Option 2 is less complex.

Option 1 (Associative Array Name Passed as Argument)

Invocation

declare -A CONFIG
load-config CONFIG
echo ${CONFIG["SOMETHING"]}

Function Declaration

function load-config() {
  local map_var_name=$1
  declare -A | grep -q "declare -A ${map_var_name}" || fail "no ${map_var_name} associative array declared"
  local key="SOMETHING"
  local value="BLAH"
  eval "${map_var_name}[\"${key}\"]=${value}"
}

Option 2 (Associative Array is Set up by Calling Layer)

Invocation

declare -A CONFIG
load-config
echo ${CONFIG["SOMETHING"]}

Function Declaration

function load-config() {
  declare -A | grep -q "declare -A CONFIG" || fail "no CONFIG associative array declared"
  local key="SOMETHING"
  local value="BLAH"
  CONFIG[${key}]=${value}
}