ios - 如何根据 id 或基于位置更新 NSMutableArray 数据

Question

我有如下 NSMutableArray 数据。

(
        {
        Id = 3;
        Name = Fahim;
    },
        {
        Id = 2;
        Name = milad;
    },
        {
        Id = 1;
        Name = Test;
    }
)

现在我想将名称从 Test 更新为 Omar（对于 id = 1）。

知道如何完成这项工作吗？

---

回答

有了以下答案，我得到了错误-[__NSDictionaryI setObject:forKey:]: unrecognized selector sent to instance。为了解决这个问题，我[feeds addObject:[item copy]]改为[feeds addObject:item]

Answer 1

for (NSMutableDictionary* aDict in yourMutableArray) {
    if (aDict[@"id"] == 1) {
        [aDict setObject:@"Omar" forKey:@"Name"];
    }
}

编辑 ：

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

NSDictionary* item1Dict = [NSDictionary dictionaryWithObjectsAndKeys:
                           @"1",@"id",
                           @"Fahim",@"name"
                           , nil];

NSMutableDictionary* item1 = [NSMutableDictionary dictionaryWithDictionary:item1Dict];

[mutableArray addObject:item1];

NSDictionary* item2Dict = [NSDictionary dictionaryWithObjectsAndKeys:
                           @"2",@"id",
                           @"milad",@"name"
                           , nil];

NSMutableDictionary* item2 = [NSMutableDictionary dictionaryWithDictionary:item2Dict];

[mutableArray addObject:item2];

NSDictionary* item3Dict = [NSDictionary dictionaryWithObjectsAndKeys:
                           @"3",@"id",
                           @"test",@"name"
                           , nil];

NSMutableDictionary* item3 = [NSMutableDictionary dictionaryWithDictionary:item3Dict];

[mutableArray addObject:item3];

NSLog(@"%@",mutableArray);

for (NSMutableDictionary* aDict in mutableArray) {
    if ([aDict[@"id"] isEqualToString:@"3"]) {
        [aDict setObject:@"Omar" forKey:@"name"];
    }
}

NSLog(@"%@",mutableArray);

并且非常优雅：

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

NSArray* name = [NSArray arrayWithObjects:@"Fahin",@"milad",@"test", nil];

for (int i = 0; i < name.count; i++) {
    NSDictionary* itemd = [NSDictionary dictionaryWithObjectsAndKeys:
                               [NSString stringWithFormat:@"%i",i],@"id",
                               name[i],@"name"
                               , nil];

    NSMutableDictionary* item = [NSMutableDictionary dictionaryWithDictionary:itemd];
    //or
    //NSMutableDictionary* item = [item mutableCopy];
    [mutableArray addObject:item];
}

NSLog(@"%@",mutableArray);

for (NSMutableDictionary* aDict in mutableArray) {
    if ([aDict[@"id"] isEqualToString:@"2"]) {
        [aDict setObject:@"Omar" forKey:@"name"];
    }
}

NSLog(@"%@",mutableArray);

日志是：

2013-10-18 00:51:48.845 test[34919:60b] (
        {
        id = 1;
        name = Fahim;
    },
        {
        id = 2;
        name = milad;
    },
        {
        id = 3;
        name = test;
    }
)

第二个日志：

2013-10-18 00:52:06.887 test[34919:60b] (
        {
        id = 1;
        name = Fahim;
    },
        {
        id = 2;
        name = milad;
    },
        {
        id = 3;
        name = Omar;
    }
)

EDIT2 复制：

-copy，由可变的 Cocoa 类实现，总是返回它们不可变的对应物。当一个 NSMutableDictionary 被发送 -copy 时，它返回一个包含相同对象的 NSDictionary。NSMutableDictionary 是 NSDictionary 的子类，编译器不会抱怨。NSDictionary 不承认它是可变子类的方法（因为它不能改变它的内容）。