变量作为bash数组索引? [英] Variable as bash array index?

问题描述

#!/bin/bash

set -x

array_counter=0
array_value=1

array=(0 0 0)

for number in ${array[@]}
do
    array[$array_counter]="$array_value"
    array_counter=$(($array_counter + 1))
done

在上述脚本上运行时，我得到以下调试输出:

When running above script I get the following debug output:

+ array_counter=0
+ array_value=1
+ array=(0 0 0)
+ for number in '${array[@]}'
+ array[$array_counter]=1
+ array_counter=1
+ for number in '${array[@]}'
+ array[$array_counter]=1
+ array_counter=2
+ for number in '${array[@]}'
+ array[$array_counter]=1
+ array_counter=3

为什么变量 $ array_counter 在用作数组[]的索引时不扩展?

Why does the variable $array_counter not expand when used as index in array[]?

推荐答案

Bash似乎很满意将变量作为数组索引:

Bash seems perfectly happy with variables as array indexes:

$ array=(a b c)
$ arrayindex=2
$ echo ${array[$arrayindex]}
c
$ array[$arrayindex]=MONKEY
$ echo ${array[$arrayindex]}
MONKEY

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