concatenate variable into single variable separated by comma with for loop

Question

I want to add the values to a variable, separated by comma, using for loop. First values should remain first and so on.

for ((i=0; i<${#MYARRAY[@]}; i++));
do
  ALL=$ALL$MYARRAY$i,
done
echo $ALL

I expect the output val1,val2,val3 but the actuel output is val1,val2,val3,

How to avoid the comma after the last value?

Answer 1

Just add one of the three statements after your for loop:

1. ALL=${ALL%,}

2. ALL=${ALL::-1}

3. ALL=${ALL%?}