Removing properties that start with "Column

I guess I'm missing something here. Perhaps someone can explain...

I wanted to remove columns that start with "Column" (i.e. columns that didn't have names in the file). This is my solution, based on a previous thread:

resize(@props_to_remove,0);

for #i in 1 .. NumProperties()

loop

if IthPropertyName(#i) RLIKE '^Column'

then

append(@props_to_remove, IthPropertyName(#i)); end if;

end loop;

RemoveDuplicates(@props_to_remove);

Remove(@props_to_remove);

This works, but what I don't get is why the following simpler solution didn't:  (I'm guessing I didn't get quotes right...)

FOR #i IN REVERSE 1 .. NumProperties()

LOOP

    IF IthPropertyName(#i) RLIKE '^Column' THEN

        remove(IthPropertyName(#i));

    END IF;

END LOOP;

Anyone care to enlighten me?