如何根据 bash 中的数组名称执行不同的操作？

Question

目前我有一个对数组名称进行硬编码以执行特定操作的函数。我想将需要处理的数组名作为函数参数传递，然后根据数组名执行特定的动作。如何在 bash 中实现这一点？

现在：

# array definition
declare -A array1=(
 ["a"]="apple"
 ["b"]="banana"
)

# function definition
process(){
    echo "printing letters and fruits"
    for letter in "${!array1[@]}"; do
        fruit="${array1[$letter]}"
        echo "$letter: $fruit"
    done
}

# commands
process

想要的（代码错误！）：

# array definition
declare -A array1=(
 ["a"]="apple"
 ["b"]="banana"
)

declare -A array2=(
 ["a"]="ant"
 ["b"]="bear"
)

# function definition
process(){
     arrayname="$1"
     case "$arrayname" in
         "array1")
             echo "printing letters and fruits"
             for letter in "${!arrayname[@]}"; do
                 fruit="${arrayname[$letter]}"
                 echo "$letter: $fruit"
             done
         ;;
         "array2") 
             echo "printing animals only"
             for letter in "${!array1[@]}"; do
                 animal="${array2[$letter]}"
                 echo "$animal"
             done
         ;;
    esac
}

# commands
process array1
process array2

Answer 1

你必须做两件事：首先，清理你的变量名——有时你在process函数中使用arrayname，有时是array1或array2。其次，使用declare 或local 制作一个nameref（一个特殊的变量，当设置为另一个变量的名称时，其作用类似于那个）：

#!/usr/bin/env bash

# array definition
declare -A array1=(
 ["a"]="apple"
 ["b"]="banana"
)

declare -A array2=(
 ["a"]="ant"
 ["b"]="bear"
)

# function definition
process(){
     local -n arrayname="$1"
     case "$1" in
         "array1")
             echo "printing letters and fruits"
             for letter in "${!arrayname[@]}"; do
                 fruit="${arrayname[$letter]}"
                 echo "$letter: $fruit"
             done
         ;;
         "array2")
             echo "printing animals only"
             for letter in "${!arrayname[@]}"; do
                 animal="${arrayname[$letter]}"
                 echo "$animal"
             done
         ;;
    esac
}

# commands
process array1
process array2