Creating Arrays From Unknown Number of External Lists - arrays

Question

this is another question related to importing values from a text file (similar to one of my previous ones), but with added complexity (the more I learn about bash scripting the more challenging it becomes)
The goal: to create an array of Day_.... on each outer loop iteration. I'm trying to do this assuming no knowledge of how many Day_... lists exist in the *.txt file.
The issue: At the moment my inner loop only iterates once (should iterate as the number of elements on Monday. And, also, I'm using my_sub_dom=$( sed 's/=.*//' weekly.txt ) to get the number of lists/arrays in weekly.txt and then filter the ones that contain Day.
Bash script:
#!/bin/bash
source weekly.txt
declare -a my_sub_dom
day=( ${Monday[*]} )
my_sub_dom=$( sed 's/=.*//' weekly.txt ) # to construct a list of the number of of lists in the text file
#echo "${my_sub_dom}"
counter=0
main_counter=0
for i in "${day[#]}"
do
let main_counter=main_counter+1
for j in "${my_sub_dom[#]}"
do
# echo "$j"
if grep -q "Day" "${my_sub_dom}"
then
echo "$j"
sub_array_name="${my_sub_dom[counter]}" # storing the list name
sub_array_content=( ${sub_array_name[*]} )
echo "${sub_array_content}"
else
echo "no"
fi
let counter=counter+1
done
echo "$counter"
counter=0
done
echo "$main_counter"
Text file format:
Day_Mon=( "google" "yahoo" "amazon" )
Day_Tu=( "cnn" "msnbc" "google" )
Day_Wed=( "nytimes" "fidelity" "stackoverflow" )
Monday= ( "one" "two" "three" )
....
Script output:
grep: Day_Mon
Day_Tu
Day_Wed
Monday: No such file or directory
no
1
grep: Day_Mon
Day_Tu
Day_Wed
Monday: No such file or directory
no
1
grep: Day_Mon
Day_Tu
Day_Wed
Monday: No such file or directory
no
1
3
Please let me know if you'd like any other information.... And I really appreciate any input in this matter, I've been trying this for a couple of days now.
Thank you

Answer 1

Given a file weekly.txt containing
Day_Mon=( "google" "yahoo" "amazon" )
Day_Tu=( "cnn" "msnbc" "google" )
Day_Wed=( "nytimes" "fidelity" "stackoverflow" )
Monday=( "one" "two" "three" )
You can loop through each array named Day_-something with
#!/bin/bash
# Set all arrays defined in the file
source weekly.txt
# Get all variables prefixed with "Day_" (bash 4)
for name in "${!Day_#}"
do
echo "The contents of array $name is: "
# Use indirection to expand the array
arrayexpansion="$name[#]"
for value in "${!arrayexpansion}"
do
echo "-- $value"
done
echo
done
This results in:
The contents of array Day_Mon is:
-- google
-- yahoo
-- amazon
The contents of array Day_Tu is:
-- cnn
-- msnbc
-- google
The contents of array Day_Wed is:
-- nytimes
-- fidelity
-- stackoverflow