原始字典

        NSDictionary *dict = @{@"name":@"qyang",
                               @"age":@"28",
                               @"sex":@"man",
                               @"other":@"hello",
                               };

1、遍历与查找

        //使用代码块遍历key-value
        [dict enumerateKeysAndObjectsUsingBlock:^(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
            NSLog(@"%@ = %@",key,obj);
            if ([obj isEqualToString:@"qyang"]) {
                *stop = YES;
            }
        }];

2、对key进行排序

        //对key进行排序
        NSArray *keysArr = [dict keysSortedByValueUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
            //
            if ([obj1 length] > [obj2 length]) {
                return NSOrderedAscending;
            }
            else if ([obj1 length] == [obj2 length]) {
                return NSOrderedSame;
            }
            else {
                return NSOrderedDescending;
            }
        }];
        NSLog(@"keysArr = %@",keysArr);

打印结果为

keysArr = (
    other,
    name,
    sex,
    age
)

3、对key进行过滤

        //对key进行过滤
        NSSet *keysSet = [dict keysOfEntriesPassingTest:^BOOL(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
            return (BOOL)([obj length]>3);
        }];
        NSLog(@"keysSet = %@",keysSet);

打印结果为

keysSet = {(
    other,
    name
)}

End