如何在Linux中访问循环中的变量值？

Question

我尝试使用如下循环获取shell脚本中的变量值：

#!/bin/bash

VR1a=1.5
VR2a=8.3
VR3a=15

VR1b=0.9
VR2b=5.7
VR3b=20

for j in a b
do
 VR1="VR1$j"
 VR2="VR2$j"
 VR3="VR3$j"
 echo ${!VR1}
 echo ${!VR2}
 echo ${!VR3}

done

我希望得到的输出是：

For variable a VR1=1.5, VR2=8.3 and VR3=15
For variable b VR1=0.9, VR2=5.7 and VR3=20

但结果是：

For variable a VR1=VR1a, VR2=VR2a and VR3=VR3a
For variable b VR1=VR1b, VR2=VR2b and VR3=VR3b

我怎样才能得到数字而不是变量名？

Answer 1

使用nameref变量：

#!/usr/bin/env bash

VR1a=1.5
VR2a=8.3
VR3a=15

VR1b=0.9
VR2b=5.7
VR3b=20

for j in a b
do
 typeset -n VR1="VR1$j"
 typeset -n VR2="VR2$j"
 typeset -n VR3="VR3$j"
 echo ${VR1}
 echo ${VR2}
 echo ${VR3}
done

或者使用关联数组：

#!/usr/bin/env bash

typeset -A VR
VR["1a"]=1.5
VR["2a"]=8.3
VR["3a"]=15
VR["1b"]=0.9
VR["2b"]=5.7
VR["3b"]=20

for j in a b
do
 echo "${VR["1$j"]}"
 echo "${VR["2$j"]}"
 echo "${VR["3$j"]}"
done