For loops in CodeBuild with a static array

Similar to this answer to a related question: https://stackoverflow.com/a/59968374/2092250

My question is, is it possible to specify to the array to loop over as a vanilla list?

So instead of:

- folders=`ls`
- for value in $folders;
   do
      echo $value;
   done
- echo "run the next command"

I'd like to do:

- folders=[a,b,c]
- for value in $folders;
   do
      echo $value;
   done
- echo "run the next command"

I'm new to YAML/CodeBuild, so I assume this is possible and I just have the syntax wrong somehow.