But there's another alternative, hence this photo.
I don't know what the proper terms are, but in the photo, you can see poles holding drying laundry. I'm guessing that you attach the laundry with large clothes pins while the pole I still inside the apartment, and when it's full, you stick it outside and stick it in the holder thingie.
I suspect these only or mostly exist in HDB housing, ie less-expensive public housing for Singaporeans and PRs. Our complex doesn't have them.