正则表达式

正则表达式Regular Expression2016 1 4正则表达式：是对字符串操作的⼀种逻辑公式，就是⽤事先定义好的⼀些特定字符、及这些特定字符的组合，组成⼀个’规则的字符串’，这个’规则字符串’⽤来对字符串的⼀种过滤逻辑。

OC1.NSString带有options选项的⼀般都⽀持正则表达式特点：只匹配第⼀个，可指定是否区分⼤⼩写。

可替换字符串。

2.NSRegularExpression类特点：能匹配多个结果，替换内容等，它是OC中实现正则表达式功能最全⾯的类3.NSPredicate类的matches命令特点：重在检索数据3个类⽤的都是ICU(international components for unicode)NSString的options选项//是否以某字符串开头，不区分⼤⼩写，当前语⾔环境NSLog(@"localeIdentifier：%@", [NSLocale currentLocale].localeIdentifier);///<当前环境en_USNSString *str = @"qwer.我们com123";//以英⽂字母开头//NSRegularExpressionSearch 只能和 NSAnchoredSearch(以某字符串开头)/NSCaseInsensitiveSearch(忽略⼤⼩写)选项配合使⽤,其它选项⽆效;//如果不使⽤NSRegularExpressionSearch时, NSAnchoredSearch可配合 NSBackwardsSearch//locale是NSLocale对象, 代理语⾔环境, NSString是处理字符串的, 区分语⾔环境是可以理解的.NSRange range = [str rangeOfString:@"[a-z]" options:NSRegularExpressionSearch | NSCaseInsensitiveSearch | NSAnchoredSearch range:NSMakeRange(0, [str length]) locale:[NSLocale currentLocale]];NSLog(@"en_US Range:%@", NSStringFromRange(range));//使⽤中⽂环境，结果相同NSRange range0 = [str rangeOfString:@"[a-z]" options:NSRegularExpressionSearch | NSCaseInsensitiveSearch | NSAnchoredSearch range:NSMakeRange(0, [str length]) locale:[NSLocale localeWithLocaleIdentifier:@"zh_CN"]];NSLog(@"zh_CN Range:%@", NSStringFromRange(range0));//断⾔、检索、替换BOOL exist = range0.location != NSNotFound;if (exist) {NSString *subString = [str substringWithRange:range0];NSString *newString = [str stringByReplacingCharactersInRange:range0 withString:@"_ReplaceString_"];NSLog(@"\n断⾔：%@, \n检索：%@, \n替换结果：%@", exist?@"true":@"false", subString, newString);} else {NSLog(@"不是以字母开头");}打印结果：localeIdentifier：en_USen_US Range:{0, 1}zh_CN Range:{0, 1}断⾔：true，检索：q，替换结果：_ReplaceString_wer.我们com123NSRegularExpression类//optionstypedef NS_OPTIONS(NSUInteger, NSMatchingOptions) {NSMatchingReportProgress = 1<<0, // block NSMatchingReportCompletion = 1 << 1, // block NSMatchingAnchored = 1 << 2, // NSMatchingWithT ransparentBounds = 1 << 3, // NSMatchingWithoutAnchoringBounds = 1 << 4// ^ $};//enumerateMatchesInString block flagstypedef NS_OPTIONS(NSUInteger, NSMatchingFlags) {NSMatchingProgress = 1 << 0, //NSMatchingCompleted = 1 << 1, //NSMatchingHitEnd = 1 << 2, //NSMatchingRequiredEnd = 1 << 3, // NSMatchingInternalError = 1 << 4//};使⽤正则搜索字符串//使⽤block获得第⼀个匹配对象的range，迭代每次计算过程– enumerateMatchesInString:options:range:usingBlock://返回匹配数据：matches中存有所有匹配的结果的range{49, 2}{52, 2}{58, 2}– matchesInString:options:range://匹配总数：在给定范围的字符串中，匹配到的个数– numberOfMatchesInString:options:range://匹配第⼀个，不过返回的是NSTextCheckingResult//该类能：检测到匹配类型，如URL/⼿机号等//match中存有第⼀个匹配的结果的range– firstMatchInString:options:range://匹配第⼀个：得到第⼀个匹配的词的内容(ac)– rangeOfFirstMatchInString:options:range:搜索A：//⽰例字符串NSString *exampleString = @"Hello, everybody. Today I wanna have a speech.DA ac AC Ca aD";//正则表达式NSError *error = NULL;NSString *pattern = @"\\b(a|b)(c|d)\\b";NSRegularExpression *rex = [NSRegularExpression regularExpressionWithPattern:patternoptions:NSRegularExpressionCaseInsensitive error:&error]; //默认使⽤NSRegularExpression *rex1 = [[NSRegularExpression alloc] initWithPattern:patternoptions:NSRegularExpressionCaseInsensitive error:&error];//在给定范围的字符串中，匹配到的个数NSUInteger numberOfMatches = [rex numberOfMatchesInString:exampleString options:0 range:NSMakeRange(0, [exampleString length])];NSLog(@"%lu", (unsigned long)numberOfMatches);//得到第⼀个匹配的词的内容(ac)NSRange rangeOfFirstMatch = [rex rangeOfFirstMatchInString:exampleString options:0 range:NSMakeRange(0, [exampleString length])];if(!NSEqualRanges(rangeOfFirstMatch, NSMakeRange(NSNotFound, 0))) {NSString *subStringForFirstMatch = [exampleString substringWithRange:rangeOfFirstMatch];NSLog(@"subStringForFirstMatch:%@", subStringForFirstMatch);} else {NSLog(@"%ld", (long)NSNotFound);}搜索B：//matches中存有所有匹配的结果的range{49, 2}{52, 2}{58, 2}NSArray *matches = [rex matchesInString:exampleString options:0 range:NSMakeRange(0, [exampleString length])];NSLog(@"NSArray:%@", matches);for (NSTextCheckingResult *match in matches) {NSRange matchRange = [match range];NSLog(@"matchesInString:%lu,%lu", (unsigned long)matchRange.length, (unsigned long)matchRange.location);}//match中存有第⼀个匹配的结果的rangeNSTextCheckingResult *match = [rex firstMatchInString:exampleString options:0 range:NSMakeRange(0, [exampleString length])];if (match) {NSRange matchRange = [match range];NSLog(@"%lu,%lu", matchRange.location, matchRange.length);}//使⽤block获得第⼀个匹配对象的range，block执⾏次数为匹配个数__block NSUInteger count = 0;[rex enumerateMatchesInString:exampleString options:0 range:NSMakeRange(0, [exampleString length]) usingBlock:^(NSTextCheckingResult * _Nullable result, NSMatchingFlags flags, BOOL * _Nonnull stop) {NSRange matchRange = [match range];NSLog(@"Block:%lu, %lu", matchRange.location, matchRange.length);if (++count >= 100) *stop = YES;}];使⽤正则替换字符串//使⽤Template替换匹配到的字符串返回替换后的字符串，源字符串不变// $0 representing the contents of the overall matched range, $1 representing the contents of the first capture group- stringByReplacingMatchesInString:options:range:withTemplate://直接在源字符串替换，返回NSUInteger类型，获得替换的次数– replaceMatchesInString:options:range:withTemplate://在string中查找由result＋offset指定的字符串，返回template指定的字符串(⽐如$0-9)- replacementStringForResult:inString:offset:template:替换A：//正则表达式NSError *error = NULL;NSString *pattern = @"\\b(a|b)(c|d)\\b";NSRegularExpression *rex = [[NSRegularExpression alloc] initWithPattern:patternoptions:NSRegularExpressionCaseInsensitive error:&error];//使⽤模版替换字符串// $0 representing the contents of the overall matched range, $1 representing the contents of the first capture groupNSString *modifiedString = [rex stringByReplacingMatchesInString:exampleString options:0 range:NSMakeRange(0, [exampleString length]) withTemplate:@"$0.$1.$2.$0"];NSString *modifiedString1 = [rex stringByReplacingMatchesInString:exampleString options:0 range:NSMakeRange(0, [exampleString length]) withTemplate:@“7"];//得到替换的次数,源字符串被替换，这⾥的源字符串是NSMutableStringNSUInteger count = [rex replaceMatchesInString:[NSMutableString stringWithString:exampleString] options:0range:NSMakeRange(0, 54) withTemplate:@"1"];NSLog(@"count:%lu", (unsigned long)count);替换B：//正则表达式NSError *error = NULL;NSString *pattern = @"\\b(a|b)(c|d)\\b";NSRegularExpression *rex = [[NSRegularExpression alloc] initWithPattern:patternoptions:NSRegularExpressionCaseInsensitive error:&error];//直接在源字符串⾥替换NSMutableString *s1 = [NSMutableString stringWithString:exampleString];NSUInteger count = [rex replaceMatchesInString:s1 options:0 range:NSMakeRange(0, 54) withTemplate:@"1"];NSLog(@"%@", s1);NSLog(@"count:%lu", (unsigned long)count);// 在 string 中查找由 result + offset 指定的字符串, 返回 template 指定的字符串(⽐如$0-9等);NSTextCheckingResult *TCResult = [rex firstMatchInString:exampleString options:0 range:NSMakeRange(0, [exampleString length])];NSString *mulString = [rex replacementStringForResult:TCResult inString:exampleString offset:0 template:@"$0_$1_$2"];使⽤正则转义//获得加⼊反义字符的替换模版+ escapedTemplateForString://获得转义后的pattern+escapedPatternForString:转义//⽰例字符串NSString *exampleString = @"Hello, everybody. Today I wanna have a speech.DA ac AC Ca aD";//获得转义后的模版NSString *TemString = [NSRegularExpression escapedTemplateForString:@"__(?.ee])__"];NSLog(@"TemString:%@", TemString);//获得转义后的PatternNSString *patString = [NSRegularExpression escapedPatternForString:@".DA"];NSLog(@"patString:%@", patString);NSRegularExpression *rex0 = [NSRegularExpression regularExpressionWithPattern:patStringoptions:NSRegularExpressionCaseInsensitive error:nil];NSLog(@"Model:%@", exampleString);NSLog(@"AfterRepalcing:%@", [rex0 stringByReplacingMatchesInString:exampleString options:0 range:NSMakeRange(0, [exampleString length]) withTemplate:TemString]); //查找数组中包含单词最多的元素,单词以空格分隔.NSArray *words = @[@"a bc ccc", @" a b aabb e", @"hello"];__block int maxCount = 0;__block int index = 0;NSString *pattern = [NSRegularExpression escapedPatternForString:@"\\s*\\w+\\s*"];NSLog(@"pattern:%@", pattern);[words enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {NSRegularExpression *rex = [NSRegularExpression regularExpressionWithPattern:@"\\s*\\w+\\s*"options:NSRegularExpressionCaseInsensitive error:nil];NSArray *result = [rex matchesInString:obj options:0 range:NSMakeRange(0, [obj length])];if (maxCount < result.count) {maxCount = (int)result.count;index = (int)idx;}}];NSLog(@"maxCount:%d, words[%d] = %@", maxCount, index, words[index]);匹配到每⼀个单词：@"\\s*\\w+\\s*NSPredicate类的matches命令//给定⼀个字符串NSString *email = @“silence-m.e@";//邮箱的正则表达式NSString *rex = @“^[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}$";//使⽤谓词进⾏匹配NSPredicate *predicate = [NSPredicate predicateWithFormat:@"self matches %@", rex];//查看是否匹配BOOL isValid = [predicate evaluateWithObject:email];NSLog(@"%d", isValid);Special Characters 特殊字符* ? + [ () {} ^ $ | \ . /正则表达式中的保留字，这些字符被⽤作⾼级匹配模式。