object-c 之 NSMutableArray

//1 创建指定容量大小的可变数组对象  开始时候申请的内存大小 可以根据以后情况进行扩展
        NSMutableArray *array = [[NSMutableArray alloc]initWithCapacity:20];

 //2 添加数组元素
        [array addObject:@"one"];
        NSLog(@"array = %@",array);

      //3 在指定下标处 插入元素
        [array insertObject:@"two" atIndex:1];
        NSLog(@"array  =%@",array);

        //4 添加传入数组的所有元素到数组中
        [array addObjectsFromArray:array];
         NSLog(@"array = %@",array);

        //5 删除最后一个元素
        [array removeLastObject];
        NSLog(@"array = %@",array);

        //6  删除指定位置
        [array removeObjectAtIndex:0];
         NSLog(@"array = %@",array);
        NSMutableArray * array1 = [NSMutableArray arrayWithObjects:@"one",@"two",@"three",@"four",@"five",@"one", nil];

        //7 删除数组中所有出现的目标元素
        [array1 removeObject:@"one"];
        NSLog(@"array1 = %@",array1);

       // 8  删除某个范围内 目标元素
        [array1 removeObject:@"one" inRange:NSMakeRange(4, 2)];
        NSLog(@"array1 = %@",array1);

        //9  删除数组中某个范围
        [array1 removeObjectsInRange:NSMakeRange(0, 3)];
        NSLog(@"array1 = %@",array1);
        //10 删除 传入输出数组在数组中的元素
        [array1 removeObjectsInArray:array];
        NSLog(@"array1 = %@",array1);

        //11 删除所有元素
        [array1 removeAllObjects];
        NSLog(@"array1 = %@",array1);

        //12 修改或重置数组
        [array setArray:array];
        NSLog(@"array = %@",array);

        //13 交换指定位置的元素
        [array1 exchangeObjectAtIndex:0 withObjectAtIndex:1];
        NSLog(@"array1 = %@",array1);

        //一个数组替换一个范围
        [array1 replaceObjectsInRange:NSMakeRange(1, 2) withObjectsFromArray:@[@"ni",@"hao"]];
        NSLog(@"array1 = %@",array1);

        //使用传入元素 替换某个下标的元素
       [array1 replaceObjectAtIndex:1 withObject:@"one"];
        NSLog(@"array1 = %@",array1);
        

        //下标集合
        NSMutableIndexSet *indexSet = [NSMutableIndexSet indexSetWithIndex:1];
        [indexSet addIndex:3];
        [indexSet addIndex:5];
        
        [array1 insertObjects:@[@"1",@"3",@"5"] atIndexes:indexSet];
        NSLog(@"array1 = %@",array1);
        
        [array1 removeObjectsAtIndexes:indexSet];
        NSLog(@"array1 = %@",array1);
        

注意：可变数组在for - in循环是不可以改变器内部元素，如果要改变，用枚举器

//将sectionTitles中数字字符串换成汉字字符串，按顺序

NSDictionary *regionDicts = @{@"19764":@"美洲",@"20954":@"韩日",@"20691":@"香港",@"21062":@"台湾",@"19774":@"中国",@"20681":@"欧洲"};
        NSMutableArray* sectionTitles = [NSMutableArray arrayWithObjects:@"20954",@"19764",@"20681",@"20691",@"21062",@"19774", nil];
        NSArray *regionAllKey = [regionDicts allKeys];
        
        for (NSString *regionKey in regionAllKey) {
            
            
            [sectionTitles enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
                if ([obj isEqualToString:regionKey]) {
                    *stop = YES;
                    if (*stop) {
                        [sectionTitles replaceObjectAtIndex:idx withObject:[regionDicts objectForKey:regionKey]];
                    }
               }
        }
        NSLog(@"调换后的sectionTitles = %@",sectionTitles);