如何在 Objective-C 中反转 NSArray？

Question

I need to reverse my NSArray.

As an example:

[1,2,3,4,5] must become: [5,4,3,2,1]

What is the best way to achieve this?

转载于:https://stackoverflow.com/questions/586370/how-can-i-reverse-a-nsarray-in-objective-c

Answer 1

For obtaining a reversed copy of an array, look at danielpunkass' solution using reverseObjectEnumerator.

For reversing a mutable array, you can add the following category to your code:

@implementation NSMutableArray (Reverse)

- (void)reverse {
    if ([self count] <= 1)
        return;
    NSUInteger i = 0;
    NSUInteger j = [self count] - 1;
    while (i < j) {
        [self exchangeObjectAtIndex:i
                  withObjectAtIndex:j];

        i++;
        j--;
    }
}

@end