通过字典键对可变数组进行排序 [英] Sorting mutable array by dictionary key

问题描述

我已经使用NSMutableArray的各种排序方法仔细查看了一些答案，但是由于某些原因，它们对我不起作用.

I have already looked through a few answers using the various sorting methods of NSMutableArray, but for some reason they are not working for me.

我只是想通过每个字典中的Delay键对包含字典的可变数组进行排序.但是，排序"数组与原始数组完全相同.

I am just trying to sort the mutable array which contains dictionaries by the Delay key within each dictionary. However, the "sorted" array is the exact same as the original array.

顺便说一句，如果我创建了一个虚拟可变数组并用包含数字的字典填充它，则可以很好地工作，但是由于某种原因，它不会对我正在初始化的可变数组进行排序.

By the way, it works fine if I create a dummy mutable array and populate it with dictionaries containing numbers, but for some reason it won't sort this mutable array that I am initializing.

我在做什么错了?

这是我的代码:

playlistCalls = [[NSMutableArray alloc] initWithArray:[currentPlaylist objectForKey:@"Tunes"]];

NSLog(@"original %@", playlistCalls);

NSSortDescriptor *delay = [NSSortDescriptor sortDescriptorWithKey:@"Delay" ascending:YES];
[playlistCalls sortUsingDescriptors:[NSArray arrayWithObject:delay]];

NSLog(@"sorted %@", playlistCalls);

这是包含字典的数组:

2012-06-04 15:48:09.129 MyApp[57043:f503] original (
        {
        Name = Test Tune;
        Delay = 120;
        Volume = 100;
    },
        {
        Name = Testes;
        Delay = 180;
        Volume = 100;
    },
        {
        Name = Testing;
        Delay = 60;
        Volume = 100;
    }
)

2012-06-04 15:48:09.129 MyApp[57043:f503] sorted (
        {
        Name = Test Tune;
        Delay = 120;
        Volume = 100;
    },
        {
        Name = Testes;
        Delay = 180;
        Volume = 100;
    },
        {
        Name = Testing;
        Delay = 60;
        Volume = 100;
    }
)

推荐答案

当我在字典中使用NSNumber时，上面的代码很好.这使我相信Delay值作为字符串存储在字典中.然后，您需要做的是按字符串integerValue排序.

The code above is fine when I use NSNumbers in my dictionary. That leads me to believe that the Delay value is stored as strings in your dictionary. What you will need to do then is sort by the strings integerValue.

NSSortDescriptor *delay = 
   [NSSortDescriptor sortDescriptorWithKey:@"Delay.integerValue" ascending:YES];

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