Question

Newb question here.

Why would I do this:

    NSPredicate *pred = [NSPredicate predicateWithFormat:@"(lineNum = %d)", i];
    [request setPredicate:pred];

When I could just do this?

    [request setPredicate:[NSPredicate predicateWithFormat:@"(lineNum = %d)", i]];

Every textbook code example I find uses the first method, but as far as I can see the second method will basically do the same thing and just looks neater. “pred” is only called once so why create it as an object?

Answer 1

This has to do primarily with the format of text books: it is hard to fit more than a certain number of characters on a page, because books have no scroll bars. Other than that, the two are identical.

One reason to do it in real life is so that you could set a break point and examine pred before calling setPredicate:.