iphone - 在不丢失索引的情况下对数组进行升序排序 Objective-C

Question

例如，我有一个数组，

    Array {
    3.0 at Index 0
    2.0 at Index 1
    3.5 at Index 2
    1.0 at Index 4
}

我想按升序对其进行排序，而不会首先丢失索引，就像这样，

    Array {
    1.0 at Index 4
    2.0 at Index 1
    3.0 at Index 0
    3.5 at Index 2
}

当我使用它对数组进行排序时，

NSArray *sortedArray = [hArray sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];
[knnRecog sortUsingDescriptors:[NSArray arrayWithObject:sortAsc]];

我丢失了索引。有谁知道在对数组进行排序后保留索引的方法吗？谢谢

Answer 1

您可以通过更改基础数据结构来进行所需的排序。考虑使用数组的数组，例如:

{    {3.0, Index 0},    {2.0, Index 1},    {3.5, Index 2},    {1.0, Index 4}}

and given a sorting function:

NSComparisonResult customCompareFunction(NSArray* first, NSArray* second, void* context)
{
    id firstValue = [first objectAtIndex:0];
    id secondValue = [second objectAtIndex:0];
    return [firstValue compare:secondValue];
}

你可以像这样排序:

NSArray* myArray = [NSArray arrayWithObjects:
                    [NSArray arrayWithObjects:
                     [NSNumber numberWithFloat:3.0f],
                     [NSNumber numberWithInt:0], nil],
                    [NSArray arrayWithObjects:
                     [NSNumber numberWithFloat:2.0f],
                     [NSNumber numberWithInt:1], nil],
                    [NSArray arrayWithObjects:
                     [NSNumber numberWithFloat:3.5f],
                     [NSNumber numberWithInt:2], nil],
                    [NSArray arrayWithObjects:
                     [NSNumber numberWithFloat:1.0f],
                     [NSNumber numberWithInt:4], nil]];

NSArray* sortedArray = [myArray sortedArrayUsingFunction:customCompareFunction context:NULL];

NSLog(@"Sorted array: %@", sortedArray);

打印内容:

排序数组:( ( 1、 4 ), ( 2、 1 ), ( 3、 0 ), ( 3.5, 2 ))