“we didn't expect you for hours” meaning in this context?

Question

"Sit down, dear, I'll knock something up."

As Harry sat down a furry ginger cat with a squashed face jumped on to his knees and settled there, purring.

"So Hermione's here?" he asked happily as he tickled Crookshanks behind the ear.

Oh yes, she arrived the day before yesterday," said Mrs Weasley, rapping a large iron pot with her wand it bounced on to the stove with a loud clang and began to bubble at once. "Everyone's in bed, of course, we didn't expect you for hours. Here you are -"

_{Harry Potter and the Half-Blood Prince}

I don't quite understand "we didn't expect you for hours" in this context. Maybe, the use of "for hours" confused me. What does it exactly mean?

Answer 1

You can understand the use of for by looking at this sequence of sentence constructions:

1. We will be working for hours.
2. We expect you to be absent for hours.
3. We did expect you to be absent for hours.
4. We didn't expect you to be absent for hours.
5. We didn't expect you to appear for hours.
6. We didn't expect you for hours.

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Of course, you can interpret the final sentence (from the quote) in two different ways.

One way is that, over a period of hours, they did not expect the person to arrive. Another way is that they did not expect the person to arrive for hours to come (they expected them to be absent for hours to come).

Whatever the interpretation is—and I'd say it's more commonly the latter—the person's arrival at the time they did arrive (at that moment rather than hours in the future) was unexpected.

Answer 2

If everyone is in bed, this scene probably takes place very late at night. Harry arrived when everyone was asleep. Mrs. Weasley says they didn’t expect him to arrive until many hours later. “For hours” means “for many hours”. “many” is understood from the plural “hours” (the amount of time is more than one hour).