Question

我正在尝试提交此对象的数组：

MyObject.h

@interface MyObject : NSObject

@property (assign) int id_object;
@property (nonatomic, strong) NSString *name;

@end

所以例如在我的firstArray中我有一些MyObject：

MyObject *ob1 = [[MyObject alloc] init];
[ob1 setId_Object:1;
[ob1 setName:@"Carl"];

MyObject *ob2 = [[MyObject alloc] init];
[ob2 setId_Object:2;
[ob2 setName:@"Carl"];

MyObject *ob3 = [[MyObject alloc] init];
[ob3 setId_Object:3;
[ob3 setName:@"Carl"];

NSArray *firstArray = [[NSArray alloc] initWithObjects:ob1,ob2,ob3,nil];

然后我希望用NSPredicate过滤这个数组，并使用NSNumber数组，如下所示：

NSArray *secondArray = [NSArray arrayWithObjects:[NSNumber numberWithInt:1],[NSNumber numberWithInt:2],nil];

我试过这个：

 NSArray *filteredObject = [firstArray filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"id_object IN %@",secondArray]];

但过滤后的对象是空的，我该怎么做？

Answer 1

检查一下，

 NSArray *filteredObject = [questionSections filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"self.Carl contains %@ OR self.Carl contains %@ ",@"1",@"2"]];

EX： -

 NSArray*  questionSections=[[NSArray alloc] initWithObjects:[[NSDictionary alloc] initWithObjectsAndKeys:
@"List 3 rooms in your house?",@"name",@"301q.png",@"questionpicture",nil],[[NSDictionary alloc] initWithObjectsAndKeys:@"Name a commonbird?",@"name",@"202q.png",@"questionpicture",nil], nil];


 NSArray *filteredObject = [questionSections filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"self.questionpicture contains %@ OR self.questionpicture contains %@ ",@"2",@"3"]];
    NSLog(@"%@",filteredObject);

O / P： -

(
        {
        name = "List 3 rooms in your house?";
        questionpicture = "301q.png";
    },
        {
        name = "Name a common bird?";
        questionpicture = "202q.png";
    }
)

Answer 2

尝试替换

@property (nonatomic, copy) NSNumber* id_object;
@property (nonatomic, copy) NSString *name;

而不是

@property (assign) int id_object;
@property (nonatomic, strong) NSString *name;

Answer 3

似乎是你的测试用例错了。我不认为你的setId_object在用NSNumber调用它时会做你的想法;

[ob1 setId_object:[NSNumber numberWithInt:1]];
NSLog(@"%d", ob1.id_object);

> 391

[ob1 setId_object:1];
NSLog(@"%d", ob1.id_object);

> 1

替换初始化会使您的测试用例运行正常。

编辑：我的测试用例，cut'n'pasted;

MyObject *ob1 = [[MyObject alloc] init]; ob1.id_object = 1; [ob1 setName:@"Carl"];
MyObject *ob2 = [[MyObject alloc] init]; ob2.id_object = 2; [ob2 setName:@"Carl"];
MyObject *ob3 = [[MyObject alloc] init]; ob3.id_object = 3; [ob3 setName:@"Carl"];

NSArray *firstArray = [[NSArray alloc] initWithObjects:ob1,ob2,ob3,nil];
NSArray *secondArray = [NSArray arrayWithObjects:[NSNumber numberWithInt:1],[NSNumber numberWithInt:2],nil];

NSArray *filteredObject = [firstArray filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"id_object IN %@",secondArray]];

NSLog(@"%@", filteredObject);

>>> <MyObject: 0x100110350> {1,"Carl"}
>>> <MyObject: 0x1001104b0> {2,"Carl"}

使用NSPredicate过滤NSArray的NSNrray对象的NSArray

3 个答案: