setMask in loop

When I use

letter1.setMask(msk1);
letter2.setMask(msk2);
letter3.setMask(msk3);

then MC “letter1” is neatly masked by MC “msk1”, “letter2” by “msk2” etc…

but how to do it in an action loop??

for (n=1; n<=_parent.parts; n++) {
letter[n].setMask(msk[n]);
}

doesn’t work

for (n=1; n<=_parent.parts; n++) {
(“letter”+n).setMask((“msk”+n));
}

doesn’t work

Can’t seem to find the right syntax, any ideas?
P