iOS应用程序中的排序数组问题

Question

我有一个类似的数组：

( "8461.86","8468.22","8468.22","8162.59","8164.50","7280.59")

我尝试按照以下顺序对该数组进行排序：

sortedArray = [arr_distance sortedArrayUsingComparator:^(id firstObject, id secondObject) {
    return [((NSString *)firstObject) compare:((NSString *)secondObject) options:NSNumericSearch];
}];

但我得到了如下数组：

( "7280.59","8162.59","8164.50","8461.86","8468.22","8468.22")

为什么会这样？

我也尝试过喜欢

return [firstObject compare:secondObject options:NSNumericSearch];

但没有得到正确的排序数组。

Answer 1

NSSortDescriptor *desc = [[NSSortDescriptor alloc]initWithKey:@"" ascending:NO];
NSMutableArray *yourTempArray = [[NSMutableArray alloc]initWithObjects:@"8459.93",@"8466.28",@"8466.28",@"8160.70",@"8162.61",@"7278.56", nil];
[yourTempArray sortUsingDescriptors:[NSArray arrayWithObject:desc]];
NSLog(@"sotedAr == %@",yourTempArray);

输出：

sotedAr == (
"8466.28",
"8466.28",
"8459.93",
"8162.61",
"8160.70",
"7278.56"

)

Answer 2

要按降序排序，您只需在代码中切换 firstObject 和 secondObject：

sortedArray = [arr_distance sortedArrayUsingComparator:^(id firstObject, id secondObject) {
  return [((NSString *)secondObject) compare:((NSString *)firstObject) options:NSNumericSearch];
}];

Answer 3

试试下面的代码：-

NSSortDescriptor *frequencyDescriptor = [NSSortDescriptor sortDescriptorWithKey:@""
                                                               ascending:NO
                                                              comparator:^(id obj1, id obj2) {
                                                                  return [obj1 compare:obj2 options:NSNumericSearch];
                                                              }];
NSEnumerator * enumerator = [arr_distance objectEnumerator];
NSArray * descriptors = [NSArray arrayWithObjects:frequencyDescriptor, nil];
NSArray * sortedArray =   [arr_distance sortedArrayUsingDescriptors:descriptors];
enumerator = [sortedArray objectEnumerator];
NSLog(@"sortedArray = %@",sortedArray);

// 使用已排序的 sortedArray

Answer 4

以下代码可能有助于按降序对数组进行排序

NSArray *arr = [NSArray arrayWithObjects:@"8459.93",@"8466.28",@"8466.28",@"8160.70",@"8162.61",@"7278.56", nil];
NSMutableArray *yourTempArray = [[NSMutableArray alloc]init];
[yourTempArray addObjectsFromArray:arr];
NSLog(@"before sorting = %@",yourTempArray);
NSSortDescriptor* sort = [NSSortDescriptor sortDescriptorWithKey: @"self" ascending: NO];

[yourTempArray sortUsingDescriptors:[NSArray arrayWithObject:sort]];
NSLog(@"After sorting = %@",yourTempArray);