Question

I’ve seen a few examples around using NSArray indexOfObjectPassingTest, but I could not make them work (they would not return a valid index).
So now I’m trying using an inline block. I have done it by typedef’ing a block, then setting it as a property, synthesizing it, and initializing it in the constructor.
However that sort of renders the whole point mute, as I could easily create a method and use it instead (less typing, less effort).

What I’m trying to achieve is something along this:

Observations *obs = [self.myAppointment.OBSERVATIONS objectAtIndex: ^NSInteger (NSString *keyword){ 
    for (Observations *obs in self.myAppointment.OBSERVATIONS) {
        if ([obs.TIME isEqualToString:keyword] == YES) return (NSInteger)[self.myAppointment.OBSERVATIONS indexOfObject:obs];
    }
    return (NSInteger)-1;
}];

However Xcode simply won’t have it. I’ve tried different variations, but declaring it inline seems to be a problem, which is weird, because as I’ve said, typedefing it, declaring, and synthesizing it works like this:

Observations *obs = [self.myAppointment.OBSERVATIONS objectAtIndex:findObs(keyword)];

Where findObs is again a defined block that does the same thing.
Is this a syntax issue, or am I missing something else more important ?

Answer 1

-objectAtIndex: takes an NSUInteger as a parameter, but you’re passing it a block (denoted by the ^). Your second example calls findObs (which may be your block) with the keyword argument, passing the result of that call to -objectAtIndex:.

You probably want to combine -objectAtIndex: with -indexOfObjectPassingTest::

NSString *keyword = /* whatever */;
NSArray *array = self.myAppointment.OBSERVATIONS;
NSUInteger idx = [array indexOfObjectPassingTest:^(id obj, NSUInteger idx, BOOL *stop){ 
    Observations *obs = (Observations*)obj;
    return [obs.TIME  isEqualToString:keyword];
}];
if (idx != NSNotFound)
    Observations *obs = [array objectAtIndex:idx];