iOS开发中使用NSEnumerator进行遍历

可复制代码：

   NSDictionary * dic = @{@"name":@"梁森", @"age":@"27"};
NSEnumerator * enumerator = [dic keyEnumerator];
id key;
while ((key = [enumerator nextObject]) != nil) {
    id value = dic[key];
    NSLog(@"value:%@", value);
}


NSArray * arr = @[@"1", @"2", @"3"];
NSEnumerator * arrEnumerator = [arr objectEnumerator];
id object;
while ((object = [arrEnumerator nextObject]) != nil) {
    NSLog(@"object:%@", object);
}

最快、最新的“块枚举法”：

  [arr enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
    NSLog(@"idx:%lu---obj:%@",idx, obj);
}];