从nsarray获取n个随机对象(例如4)

Question

我有一个大的NSArray名称,我需要从该数组中随机获得4条记录(名称),我该怎么做？

Answer 1

#include <stdlib.h>

NSArray* names = ...;
NSMutableArray* pickedNames = [NSMutableArray new];

int remaining = 4;

if (names.count >= remaining) {
    while (remaining > 0) {
       id name = names[arc4random_uniform(names.count)];

       if (![pickedNames containsObject:name]) {
           [pickedNames addObject:name];
           remaining--;
       }
    }
}