阵列枚举期间应用程序崩溃

Question

这段代码有什么问题？我明白了

 Collection <NSCFArray: 0x101e1b6d0> was mutated while being enumerated

它是NSMutableArray,而不是NSArray

NSMutableArray *set = [[NSMutableArray alloc]initWithObjects:@"first", @"second", @"third", @"third", nil];

    [set enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop)
     {
         if([obj isEqualToString:@"third"])
         {
             [set removeObjectAtIndex:idx];
         }
     }];

    [pool drain];

Answer 1

问题是你在枚举期间改变了数组.这是不行的.

请阅读选中的答案

迭代时从NSMutableArray中删除的最佳方法是什么？

你需要的就是那里.

Answer 2

在迭代它时,你不能改变(改变)一个集合,因为迭代器对象也需要改变.您应该将要删除的对象添加到数组中,然后将其删除.

NSMutableArray *set = [[NSMutableArray alloc]initWithObjects:@"first", @"second", @"third", @"third", nil];

NSMutableArray *arrayOfObjectsToRemove = [[NSMutableArray alloc] init];
[set enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop)
 {
     if([obj isEqualToString:@"third"])
     {
         [arrayOfObjectsToRemove addObject:obj];
     }
 }];

[set removeObjectsInArray:arrayOfObjectsToRemove];

[pool drain];