如何让sortedArrayUsingSelector使用整数来排序而不是String？

问题描述

我有一些这样的数据：

1,111,2,333,45,67,322,4445

1, 111, 2, 333, 45, 67, 322, 4445

NSArray *array = [[myData allKeys]sortedArrayUsingSelector: @selector(compare:)];

如果我运行此代码，它的排序方式如下：

If I run this code, it sorted like this:

但是我其实想要这个：

我该如何实现它？ thz u。

How can I implement it? thz u.

推荐答案

扩展保罗林奇的答案，这里有一个例子我使用比较方法作为一个类别的NSString 。此代码仅处理数字后跟可选的非数字限定符的情况，但如果需要，您可以扩展它以处理1a10等情况。

Expanding on Paul Lynch's answer, here's an example I have doing exactly this using a comparison method as a category on NSString. This code handles only the case of numbers followed by optional non-numeric qualifiers, but you could extend it to handle cases like "1a10" etc. if desired.

一旦你创建类别方法，你只需要做

Once you create the category method, you just need to do

[[myData的allKeys] sortedArrayUsingSelector：@selector（psuedoNumericCompare：）];

@interface NSString (Support)
- (NSComparisonResult) psuedoNumericCompare:(NSString *)otherString;
@end

@implementation NSString (Support)

// "psuedo-numeric" comparison
//   -- if both strings begin with digits, numeric comparison on the digits
//   -- if numbers equal (or non-numeric), caseInsensitiveCompare on the remainder

- (NSComparisonResult) psuedoNumericCompare:(NSString *)otherString {

    NSString *left  = self;
    NSString *right = otherString;
    NSInteger leftNumber, rightNumber;


    NSScanner *leftScanner = [NSScanner scannerWithString:left];
    NSScanner *rightScanner = [NSScanner scannerWithString:right];

    // if both begin with numbers, numeric comparison takes precedence
    if ([leftScanner scanInteger:&leftNumber] && [rightScanner scanInteger:&rightNumber]) {
        if (leftNumber < rightNumber)
            return NSOrderedAscending;
        if (leftNumber > rightNumber)
            return NSOrderedDescending;

        // if numeric values tied, compare the rest
        left = [left substringFromIndex:[leftScanner scanLocation]];
        right = [right substringFromIndex:[rightScanner scanLocation]];
    }

    return [left caseInsensitiveCompare:right];
}

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