Question

有没有办法缩短这段代码？

NSMutableArray *allobjects = [[NSMutableArray alloc] initWithCapacity:b];

    if (b == 1) {
        [allobjects addObject:object];
    }else if (b == 2){
        [allobjects addObject:object];   
        [allobjects addObject:object2];
    }else if (b == 3){

        [allobjects addObject:object];
        [allobjects addObject:object2];
        [allobjects addObject:object3];
    }else if (b == 4){

        [allobjects addObject:object];
        [allobjects addObject:object2];
        [allobjects addObject:object3];
        [allobjects addObject:object4];

    }else if (b == 5){

        [allobjects addObject:object];
        [allobjects addObject:object2];
        [allobjects addObject:object3];
        [allobjects addObject:object4];
        [allobjects addObject:object5];
    }else if (b == 6){

        [allobjects addObject:object];
        [allobjects addObject:object2];
        [allobjects addObject:object3];
        [allobjects addObject:object4];
        [allobjects addObject:object5];
        [allobjects addObject:object6];
    }else if (b == 7){

        [allobjects addObject:object];
        [allobjects addObject:object2];
        [allobjects addObject:object3];
        [allobjects addObject:object4];
        [allobjects addObject:object5];
        [allobjects addObject:object6];
        [allobjects addObject:object7];
    }else if (b == 8){

        [allobjects addObject:object];
        [allobjects addObject:object2];
        [allobjects addObject:object3];
        [allobjects addObject:object4];
        [allobjects addObject:object5];
        [allobjects addObject:object6];
        [allobjects addObject:object7];
        [allobjects addObject:object8];
    }

正如您所看到的，如果b等于1，我会添加object1，如果b为2，我会同时添加object1和object2，所以上。

Answer 1

将所有这些字符串放入C数组中：

NSString * objects[] = { object1, object2, object3, object4, object5, object6, object7, object8, object9 };

一旦你知道b的值是什么，就迭代一遍：

allObjects = [NSMutableArray array];
for( int i = 0; i < b; i++ ){
    [allObjects addObject:objects[i]];
}

或者，甚至更好，做：

allObjects = [NSMutableArray arrayWithObjects:objects count:b];

Answer 2

NSString* ojbs[] = { object1, object2, object3, object4, object5, object6, object7, object8, object9 };

int _count = 5; // for example

NSArray* arr = [NSArray arrayWithObjects: objs count: _count];
NSMutableArray* result = [NSMutableArray arrayWithCapacity: _count];
[resul addObjectsFromArray: arr];

Answer 3

NSArray *allStrings = [NSArray arrayWithObjects:object, object2, object3, object4, object5, object6, object7, object8, object9, nil];

NSArray *objects = nil;
if (b <= [allStrings count])
    objects = [allStrings subarrayWithRange:NSMakeRange(0, b)];

Answer 4

以下是两个备选答案：

1

如何动态执行此操作（假设您可以将object重命名为object0以适合该模式！）

for (uint n = 0; n < b; ++n) {
    NSString *name = [NSString stringWithFormat:@"object%i], n];
    [allObjects addObject:[self performSelector:name]];
}

但是，这在运行时比其他基于数组的答案慢（每次在viewDidLoad中都可以创建一个新的字符串时）。

2

另一种方法是使用视图的tag属性 - 然后你的循环就会变成：

for (uint n = 0; n < b; ++n) 
    [allObjects addObject:[self.view viewWithTag:n]];

Answer 5

感叹！

switch (b) {
    case 8 :
        [allobjects insertObject:object8 atIndex:0];
    case 7 :
        [allobjects insertObject:object7 atIndex:0];
    case 6 : 
        [allobjects insertObject:object6 atIndex:0];
    case 5 :
        [allobjects insertObject:object5 atIndex:0];
    case 4 :
        [allobjects insertObject:object4 atIndex:0];
    case 3 :
        [allobjects insertObject:object3 atIndex:0];
    case 2 :
        [allobjects insertObject:object2 atIndex:0];
    case 1 :
        [allobjects insertObject:object atIndex:0];
        break;
    default :
        <Signal error or whatever>
}

如果条目不需要按顺序排列，则可以使用addObject。

您还可以使用OP原始代码的变体：

if (b >= 1) [allobjects addObject:object];
if (b >= 2) [allobjects addObject:object2];
if (b >= 3) [allobjects addObject:object3];
if (b >= 4) [allobjects addObject:object4];
if (b >= 5) [allobjects addObject:object5];
if (b >= 6) [allobjects addObject:object6];
if (b >= 7) [allobjects addObject:object7];
if (b >= 8) [allobjects addObject:object8];

缩短代码以将可变数量的对象添加到NSMutableArray

5 个答案: