ios - ios sortedArrayUsingComparator但始终在开头保留一些值

Question

我正在排序这样的数组:

NSArray *temp = [array sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
    int first = [[a valueForKey:@"id"] intValue];
    int second = [[b valueForKey:@"id"]intValue];
    if (first > second) return NSOrderedAscending;
    if (first < second) return NSOrderedDescending;
    return NSOrderedSame;
}];
return [temp mutableCopy];

可以正常工作，但是现在我想添加检查以查看例如a的key值是否等于某个值，无论“id”值是什么，始终将其保持在数组的顶部。是否可以使用比较器执行此操作？

Answer 1

假设您的特定值为5，然后将代码更改为

NSArray *temp = [array sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
    int first = [[a valueForKey:@"id"] intValue];
    int second = [[b valueForKey:@"id"] intValue];
    int foo = [[a valueForKey:@"foo"] intValue]; // get foo

    if (foo == 5) return NSOrderedAscending;    // send foo to the top/bottom
    if (first > second) return NSOrderedAscending;
    if (first < second) return NSOrderedDescending;
    return NSOrderedSame;
}];
return [temp mutableCopy];