在Objective C中随机分配NSArray的规范方法

Question

有没有一种规范的方法可以在Objective C中将数组随机化？

Answer 1

我的解决方案是一个类别方法，该方法返回具有随机元素（使用arc4random）的数组的副本（自动发布）。

@interface NSArray (CMRandomised)

/* Returns a copy of the array with elements re-ordered randomly */

- (NSArray *)randomised;

@end

/* Returns a random integer number between low and high inclusive */

static inline int randomInt(int low, int high)

{

    return (arc4random() % (high-low+1)) + low;

}

@implementation NSArray (CMRandomised)

- (NSArray *)randomised

{

    NSMutableArray *randomised = [NSMutableArray arrayWithCapacity:[self count]];

    for (id object in self) {

        NSUInteger index = randomInt(0, [randomised count]);

        [randomised insertObject:object atIndex:index];

    }

    return randomised;

}

@end