export an array with dynamic array name

Question

For suppose there is a code

comp="LP"
n_names="abc456.com,def123.com,wxy098.com"
IFS=',' read -r -a n_split_list <<< "$n_names"

Now I want to export the n_split_list array with the following variable format. Remember comp need not always be "LP" . It changes based on argument given to the script.

export "$comp"_list="${n_split_list[@]}"

but the problem is coming while exporting ( only first item of the array is getting exported ) Please help!

"$comp"_list= How would you use the variable later?? You can't do echo "${${comp}_list[@]}" - that's invalid. What is the point? Remember comp need not always be "LP" sure, but why would you want to create a variable with the name of other variable? What are the array and comp meant to represent? How are they meant to be used? — KamilCuk
– KamilCuk, Commented Mar 13, 2022 at 11:55
@KamilCuk It is actually possible to do: var="${comp}_list[@]"; printf '%s\n' "${!var}". — dan
– dan, Commented Mar 13, 2022 at 14:23
You can not export an array. Only variables and functions. — dan
– dan, Commented Mar 13, 2022 at 14:26
Due to how @ works, your command is equivalent to export "$comp"_list="${n_split_list[0]}" "${n_split_list[1]}" "${n_split_list[2]}". — chepner
– chepner, Commented Mar 13, 2022 at 14:54
You could switch to *, which would make LP_list an ordinary space-delimited list of domain names, but that would defeat the purpose of using an array in the first place (and as dan points out, you cannot export an array itself). — chepner
– chepner, Commented Mar 13, 2022 at 14:55

anubhava · Accepted Answer · 2022-03-13 12:06:32Z

1

Assuming your values may contain whitespaces, you may use read again with dynamic variable name and comma as IFS:

comp="LP"
n_names="abc456.com,def123.com,w xy098.com"
IFS=',' read -r -a n_split_list <<< "$n_names"

IFS=, read -ra ${comp}_list < <(printf '%s,' "${n_split_list[@]}")

# check content of new array
declare -p ${comp}_list

declare -a LP_list=([0]="abc456.com" [1]="def123.com" [2]="w xy098.com")

Working Demo

edited Mar 13, 2022 at 12:06

answered Mar 13, 2022 at 11:45

anubhava

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3 Comments

sai akhil Over a year ago

but comp need not always be "LP" it can change. in that case?

sai akhil Over a year ago

syntax error near unexpected token `<' -- for 4th line of your code.

anubhava Over a year ago

Check working demo May be you have older bash version

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