Bash for循环设置变量，其值并对其进行评估? [英] Bash for loop to set a variable, its value, and evaluate it?

问题描述

如何使用for循环来定义变量，和其值，和并能够对其求值?

How do I use a for loop to define a variable, and its value, and be able to evaluate it?

我无法弄清楚评估部分，但是使用for循环定义变量和似乎可行.具体来说，

I can't figure out the evaluation part, but using the for loop to define the variable and its value seems to work. Specifically,

for i in {1..4}
do
    export my${i}var="./path${i}_tofile"
   # or
   # export my${i}var=./path${i}_tofile
   # or
   # eval "my${i}var=\"./path${i}_tofile\""
    echo $[my${i}var]
done

echo的计算结果不正确，但是外壳程序正确创建了变量和值.

The echo does not evaluate correctly, but the shell does correctly create the variable and the value.

echo $my1var

返回

./path1_tofile

但是我需要使用$i作为变量名称的一部分来评估变量.

But I need to evaluate the variables using the $i as part of their names.

推荐答案

如果您不使用数组，这会变得很复杂:

This is how it gets complicated if you don't use an array:

for i in {1..4}
do
    declare my${i}var="./path${i}_tofile"
    tmpvar=my${i}var             # temporary variabled needed for...
    echo "$tmpvar=${!tmpvar}"    # bash indirect variable expansion
done

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