Fill wanted line(s) colmns inside other dt loop


So I have problem with filling large datatables. I have large datatable (+500k rows) where I need to fill columns based on other column. And because of large size I can’t use for each row to do it so I’m writing here.

For example I have columns Fruit and Suitable and I need to fill yes to every apple and orange and no to peach. On other dt I have loop where I check is the fruit suitable. So I know what is column (Fruit) row name (apple) and what I need to fill to other column (yes) but I don’t know how to do it without for each row loop because that takes too long. I would need some assing like “ = key) = yes”.

And side info. There can be 1-100 same fruits on table and all wanted lines need to be filled and fruit names are dynamic, comes from othere loop where I can use item.key to get those.