可变数组NSMutableArray

  //NSMutableArray 继承至 NSArray
//        NSArray * array = @[];
        //1.创建可变数组
        NSMutableArray * array = [[NSMutableArray alloc] initWithCapacity:0];

        //使用addObject 动态给数组中增加元素
        /*
        [array addObject:@"one"];
        [array addObject:@"two"];
        [array addObject:@"three"];
        [array addObject:@"one"];
         */
        NSString * str1 = @"one";
        NSString * str2 = @"two";
        NSString * str3 = @"three";

        //数组中可以存储,同一个对象多次
        [array addObject:str1];
        [array addObject:str2];
        [array addObject:str3];
        [array addObject:str1];

        //2.指定对象插入的位置
        [array insertObject:str1 atIndex:2];

        //3.删除 会通过对象,删除数组中所有的同一个地址的对象
        [array removeObject:str1];

        //4.通过索引的方式删除对象,超出了数组的count值,那么就会导致异常 index beyond bounds
        [array removeObjectAtIndex:0];

        [array addObject:str2];
        [array addObject:str3];
        [array addObject:str1];

        //5.删除数组中所有的元素
        [array removeAllObjects];

        NSLog(@"array %@",array);

        [array addObject:str2];
        [array addObject:str3];
        [array addObject:str1];

        //1.for换遍历
        for (int i = 0; i < array.count; i++)
        {
            NSString * str = [array objectAtIndex:i];

            //在遍历数组的时候,千万不要给数组中,增加,或者删除元素
//            [array removeObject:str1];

            NSLog(@"str %@",str);

        }

        //2.增强for循环
        for (NSString * str in array)
        {
//            [array removeObject:str1];
            //如果你在增强for循环中,删除元素,会直接导致异常出现
            NSLog(@"str %@",str);
        }

        //3.枚举器

        NSEnumerator * enumerator = [array objectEnumerator];
        NSString * value;
        while (value = [enumerator nextObject]) {
            //如果你在枚举器中,删除元素,会直接导致异常出现
//            [array removeObject:str1];
            NSLog(@"str %@",value);
        }

        //4.要通过遍历的方式确定删除哪个元素怎么办

        NSMutableArray * array2 = [[NSMutableArray alloc] init];
        [array2 addObject:@"1"];
        [array2 addObject:@"2"];
        [array2 addObject:@"3"];
        [array2 addObject:@"4"];
        [array2 addObject:@"5"];

        NSMutableArray * tmp = [[NSMutableArray alloc] init];

        for (NSString * str in array2)
        {
            if ([str isEqualToString:@"3"])
            {
                [tmp addObject:str];
            }
        }

        NSLog(@"array2 %@",array2);
        NSLog(@"tmp %@",tmp);

        //遍历临时数组
        for (int i = 0; i < tmp.count; i++)
        {
            NSString * str = [tmp objectAtIndex:i];

            //从原数组中删除,临时数组中存储的对象
            [array2 removeObject:str];
        }

        NSLog(@"array2 %@",array2);