Question

我有一个像：

这样的数组

（ “8461.86”，“8468.22”，“8468.22”，“8162.59”，“8164.50”，“7280.59”）

我尝试按以下方式对此数组进行排序：

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

但我得到了以下数组：

（ “7280.59”，“8162.59”，“8164.50”，“8461.86”，“8468.22”，“8468.22”）

为什么会这样？

我也尝试使用

return [firstObject compare:secondObject options:NSNumericSearch];

但没有获得正确的排序数组。

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);

<强>输出：

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

）

Answer 2

要按降序顺序排序，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

下面的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);

Answer 4

请尝试以下代码： -

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

在iOS应用程序中排序数组问题

4 个答案: