Question

如何使用以下方法对数组进行排序，保留重复项？我想要的是对距离数组进行排序，并使lineItems数组按相同的顺序排序，以便我的行项目按距离排序。是否有捷径可寻？我尝试了很多不同的实现，没有运气。

lineItems = [[NSMutableArray alloc] initWithArray:(NSMutableArray *)[data objectForKey:@"line_items"]];
distanceArray = [[NSMutableArray alloc] initWithCapacity:[lineItems count]];
        for (int i = 0; i < [lineItems count]; i++) {
            CLLocation *spotLocation = [[CLLocation alloc] initWithLatitude:[[[lineItems objectAtIndex:i] objectForKey:@"latitude"] floatValue] longitude:[[[lineItems objectAtIndex:i] objectForKey:@"longitude"] floatValue]];
            CLLocationDistance distance = ([myLocation distanceFromLocation:spotLocation] / 1000) * 0.621371192;
            NSNumber *foo = [[NSNumber alloc] initWithDouble:distance];
            [distanceArray insertObject:foo atIndex:i];
        }

我的冒泡排序实施：

for (int i=0;i<[distanceArray count]-1;i++){
            for(int j=1;j<[distanceArray count];j++){
                if ([[distanceArray objectAtIndex:i]doubleValue] >[[distanceArray objectAtIndex:j]doubleValue]){
                    NSNumber *temp_i = [[NSNumber alloc] initWithDouble:[[distanceArray objectAtIndex:i]doubleValue]];
                    NSNumber *temp_j = [[NSNumber alloc] initWithDouble:[[distanceArray objectAtIndex:j]doubleValue]];
                    [distanceArray removeObjectAtIndex:i];
                    [distanceArray removeObjectAtIndex:j];
                    [distanceArray insertObject:temp_j atIndex:i];
                    [distanceArray insertObject:temp_i atIndex:j];

                    NSDictionary *tempObj_i = [[NSDictionary alloc] initWithDictionary:[lineItems objectAtIndex:i]];
                    NSDictionary *tempObj_j = [[NSDictionary alloc] initWithDictionary:[lineItems objectAtIndex:j]];
                    [lineItems removeObjectAtIndex:i];
                    [lineItems removeObjectAtIndex:j];
                    [lineItems insertObject:tempObj_j atIndex:i];
                    [lineItems insertObject:tempObj_i atIndex:j];
                }
            }
        }

Answer 1

您的问题不是-sortedArrayUsingSelector:，NSDictionary -allKeys方法。键在字典中是唯一的，因此-allKeys数组不会有任何重复。

使用单独的NSArray实例存储排序结果，或使用inafziger的建议。

Answer 2

请尝试以下方法，而不是使用排序功能：

[distanceArray sortArrayUsingSelector:@selector(compare:)];

然后根本不需要字典。

Answer 3

为什么不做旧的时尚泡泡排序呢？

类似的东西：

distanceArray=[NSMutableArray arrayWithOjects:[ distanceArray allKeys]];
for (int i=0;i<[distanceArray count]-1;i++){
    for(int j=1;j<[distanceArray count];j++){
        if ([[distanceArray objectAtIndex:i]floatValue] >[[distanceArray objectAtIndex:j]floatValue]){
            id temp=[[distanceArray objectAtIndex:i]floatValue];
            [distanceArray insertObject:[[distanceArray objectAtIndex:j]floatValue] atIndex:i];
            [distanceArray insertObject:temp atIndex:j];
        }
    }
}

并且它们都是重复排序的（它不漂亮但是有效）

编辑：

如果没有任何作用..制作一个客观的c对象，例如：coord1，coord2，distance，也许是一个唯一的id。所以你永远不会有一个重复的项目。将它们作为该对象的属性声明，然后对它们进行冒泡排序（也许也可以更改id-s）。如果你有一个id = 2的对象并且你在索引1的数组中移动它，那么就改变id以匹配索引...或者那样的东西。然后你不需要字典，因为你在对象本身中有coord ...它应该更容易做..至少在我的脑海里

Answer 4

我最终只是将lineItems转换为可变字典数组并将距离添加到每个行项目中。然后使用sortUsingDescriptor方法。我感谢大家的帮助！这么简单的事情对我来说太难了...谢谢：

for (int i = 0; i < [lineItems count]; i++) {
            CLLocation *spotLocation = [[CLLocation alloc] initWithLatitude:[[[lineItems objectAtIndex:i] objectForKey:@"latitude"] floatValue] longitude:[[[lineItems objectAtIndex:i] objectForKey:@"longitude"] floatValue]];
            CLLocationDistance distance = ([myLocation distanceFromLocation:spotLocation] / 1000) * 0.621371192;
            NSNumber *foo = [[NSNumber alloc] initWithDouble:distance];

            NSMutableDictionary *newLineItem = [[lineItems objectAtIndex:i] mutableCopy];
            [newLineItem setObject:foo forKey:@"distance"];
            [lineItems removeObjectAtIndex:i];
            [lineItems insertObject:newLineItem atIndex:i];
            newLineItem = nil;
        }
        [lineItems sortUsingDescriptors:[NSArray arrayWithObject:[[NSSortDescriptor alloc] initWithKey:@"distance" ascending:YES]]];

你如何防止sortedArrayUsingSelector删除重复的条目（ios）？

4 个答案: