iphone : 如何用来自其他数组的对象创建一个数组

Question

我有三个NSMutabelArrays，每个包含大约十个字符串，例如：

    1stArray = [NSMutableArray arrayWithObjects:@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i",nil];

    2ndArray = [NSMutableArray arrayWithObjects:@"j",@"k",@"l",@"m",@"n",@"o",@"p",nil];

    3rdArray = [NSMutableArray arrayWithObjects:@"q",@"r",@"s",@"t",@"u",@"v",@"w",nil];

现在我想用这 3 个 NSMutableArray 的前 2 个对象制作第 4 个 NSMutabelArrays。 例如，我想要这样的第四个数组：

4thArray = [@"a",@"b",@"j",@"k",@"q",@"r"]

如何做到这一点？

Answer 1

我认为您正在寻找这样的代码

int numElements = 2;
int numArrays = 3;

NSMutableArray * 4thArray = [NSMutableArray array];

for (int arrays = 0; arrays < numArrays; arrays++) {
    for (int count = 0; count < numElements; count++) {
        switch (arrays) {
            case 0:
                [4thArray addObject:[1stArray objectAtIndex:count]];
                break;
            case 1:
                [4thArray addObject:[2ndArray objectAtIndex:count]];
                break;
            case 2:
                [4thArray addObject:[3rdArray objectAtIndex:count]];
                break;
        }
    }
}

Answer 2

似乎使用数组数组或数组和字典的组合会更好地解决此问题，具体取决于您要实现的目标。您的问题的答案是微不足道的，因此我将向您指出 NSArray Reference，但您可能需要考虑不同的方法。

Answer 3

这样做

NSMutableArray *firstArray = [NSMutableArray arrayWithObjects:@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i",nil];
    NSMutableArray *secArray = [NSMutableArray arrayWithObjects:@"j",@"k",@"l",@"m",@"n",@"o",@"p",nil];
   NSMutableArray *thrdArray = [NSMutableArray arrayWithObjects:@"q",@"r",@"s",@"t",@"u",@"v",@"w",nil];

    NSMutableArray *fourthArr = [[NSMutableArray alloc] initWithObjects:[firstArray objectAtIndex:0],[firstArray objectAtIndex:1], [secArray objectAtIndex:0],[secArray objectAtIndex:1], [thrdArray objectAtIndex:0],[thrdArray objectAtIndex:1],nil];
    NSLog(@"%d", fourthArr.count);