use string as variable name

use string as variable name

[Frank Wunderlich]

Hi,

is it possible to use a string as variable-name?

example:

i=1
img_$i=foo

now i have defined $img_1, but how to display it using $i again?

echo ${img_$i}
echo ${img_${i}}

alternative may be a variable-array, but it seems not possible

img[$i]=bar
img[1]=bar: No such file or directory

i just want to create a dynamic list and access the items of this list by index

another way may be appending new string with separator to existing string and split afterwards,
but then i have the index-problem again.

i know barebox shell is limited (but much more mighty than expected for just a bootloader),
but maybe it is possible :)

any idea?

regards Frank


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Re: use string as variable name

[Sascha Hauer]

Hi Frank,

On Sun, Jan 23, 2022 at 10:58:36AM +0100, Frank Wunderlich wrote:
> Hi,
> 
> is it possible to use a string as variable-name?
> 
> example:
> 
> i=1
> img_$i=foo
> 
> now i have defined $img_1, but how to display it using $i again?
> 
> echo ${img_$i}
> echo ${img_${i}}
> 
> alternative may be a variable-array, but it seems not possible
> 
> img[$i]=bar
> img[1]=bar: No such file or directory
> 
> i just want to create a dynamic list and access the items of this list by index
> 
> another way may be appending new string with separator to existing string and split afterwards,
> but then i have the index-problem again.
> 
> i know barebox shell is limited (but much more mighty than expected for just a bootloader),
> but maybe it is possible :)

Nah, you're kidding, the barebox shell is not limited ;)

#!/bin/sh

list="foo bar baz"

index=$1

i=0
for elem in $list; do
        let i=$i+1
        if [ "$i" = "$index" ]; then
                result="$elem"
        fi
done

echo result: $result

Regards,
  Sascha

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