Nsstring Sort
##NSString 的比较排序在，Cocoa中有如下几种方式
###1. 使用使用数组的sortedArrayUsingComparator 再结合NSString compare 之类的方法，可以指定Option
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-(NSArray *)sortedArrayUsingComparator:(NSComparator)cmptr NS_AVAILABLE(10_6, 4_0);
- (NSArray *)sortedArrayWithOptions:(NSSortOptions)opts usingComparator:(NSComparator)cmptr NS_AVAILABLE(10_6, 4_0);
- (NSComparisonResult)compare:(NSString *)string;
- (NSComparisonResult)compare:(NSString *)string options:(NSStringCompareOptions)mask;
- (NSComparisonResult)compare:(NSString *)string options:(NSStringCompareOptions)mask range:(NSRange)compareRange;
- (NSComparisonResult)compare:(NSString *)string options:(NSStringCompareOptions)mask range:(NSRange)compareRange locale:(id)locale;
###option 是比较的规则
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enum {
NSCaseInsensitiveSearch = 1, //忽略大小
NSLiteralSearch = 2,//
NSBackwardsSearch = 4,//从后往前比较
NSAnchoredSearch = 8,
NSNumericSearch = 64,//数字和字母比较
NSDiacriticInsensitiveSearch = 128,//忽略发音，比如中文的 妈（第一声），马（第三声）
NSWidthInsensitiveSearch = 256, //忽略宽度
NSForcedOrderingSearch = 512, //
NSRegularExpressionSearch = 1024
};
###2. 在数组中使用sort方法，再结合string的selector
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- (NSArray *)sortedArrayUsingFunction:(NSInteger (*)(id, id, void *))comparator context:(void *)context;
- (NSArray *)sortedArrayUsingFunction:(NSInteger (*)(id, id, void *))comparator context:(void *)context hint:(NSData *)hint;
- (NSArray *)sortedArrayUsingSelector:(SEL)comparator;
###NSString.h
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- (NSComparisonResult)caseInsensitiveCompare:(NSString *)string;
- (NSComparisonResult)localizedCompare:(NSString *)string;
- (NSComparisonResult)localizedCaseInsensitiveCompare:(NSString *)string;
- (NSComparisonResult)localizedStandardCompare:(NSString *)string
###sortedArrayUsingFunction传递是参数是函数指针，就不一定是要某个类的selector
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NSInteger intSort(id num1, id num2, void *context)
{
int v1 = [num1 intValue];
int v2 = [num2 intValue];
if (v1 < v2)
return NSOrderedAscending;
else if (v1 > v2)
return NSOrderedDescending;
else
return NSOrderedSame;
}
###返回比较结果的NSInteger 可以对应
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enum {
NSOrderedAscending = -1, //由小到达
NSOrderedSame, //相等
NSOrderedDescending //由大到小
};
typedef NSInteger NSComparisonResult;
###而使用sortedArrayUsingSelector 就可以使用到系统提供的自己个默认的slector
###3. 使用数组的descriptor
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- (NSArray *)sortedArrayUsingDescriptors:(NSArray *)sortDescriptors; // returns a new array by sorting the objects of the receiver
NSSortDescriptor* sortDesc = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES selector:@selector(localizedCaseInsensitiveCompare:)];
###而系统这些API底层是调用ICU库实现的， 而且结合locale的参数可以实现多种不同的比较
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static NSComparisonResult compareStringByPassingLocaleName(NSString *a, NSString *b, const char *localeName)
{
NSLocale *locale = [[NSLocale alloc] initWithLocaleIdentifier:[NSString stringWithUTF8String:localeName]];
NSComparisonResult result = [a compare:b options:0 range:NSMakeRange(0, [a length]) locale:locale];
[locale release];
return result;
}
#define COMPARE(x) ((NSComparisonResult)compareStringByPassingLocaleName(self, anotherString, x))
- (NSComparisonResult)compareChineseByStrokeOrder:(NSString *)anotherString
{
return COMPARE("zh@collation=stroke");
}
- (NSComparisonResult)compareChineseByPinyinOrder:(NSString *)anotherString
{
return COMPARE("zh@collation=pinyin");
}
- (NSComparisonResult)compareChineseByBIG5Order:(NSString *)anotherString
{
return COMPARE("zh@collation=big5han");
}
- (NSComparisonResult)compareChineseByGB2312Order:(NSString *)anotherString
{
return COMPARE("zh@collation=gb2312");
}
- (NSComparisonResult)compareChineseByRadicalOrder:(NSString *)anotherString
{
return COMPARE("zh@collation=unihan");
}
#undef COMPARE
###详细代码参见
