准备工作，下载RegexKitLite
软件包，解压后有2个文件，需要加载到project中。

然后还要加载framework
libicucore.dylib
，因为RegexKitLite是调用这个里面的API,苹果规定过不能使用私有的api和没有发布的api。实际上RegexKitLite对NSString做了扩展，目前只支持NSString，对我来说也够了...

基本使用的例子（更多信息参看
官方文档

）

1.

NSString *searchString = @"This is neat.";<br /> NSString *regexString = @"(//w+)//s+(//w+)//s+(//w+)";<br /> NSRange matchedRange = NSMakeRange(NSNotFound, 0UL);<br /> NSError *error = NULL;<br /> matchedRange = [searchString rangeOfRegex:regexString options:RKLNoOptions inRange:searchRange capture:2L error:&error];<br /> NSLog(@"matchedRange: %@", NSStringFromRange(matchedRange));<br /> // 2008-03-18 03:51:16.530 test[51583:813] matchedRange: {5, 2}，//匹配到‘is‘<br /> NSString *matchedString = [searchString substringWithRange:matchedRange];<br /> NSLog(@"matchedString: '%@'", matchedString);<br /> // 2008-03-18 03:51:16.532 test[51583:813] matchedString: 'is' //生成子字符串

2.找到第一个匹配并返回一个NSString

NSString *searchString = @"This is neat.";<br /> NSString *regexString = @"(//w+)//s+(//w+)//s+(//w+)";<br /> NSString *matchedString = [searchString stringByMatching:regexString capture:2L];<br /> NSLog(@"matchedString: '%@'", matchedString);<br /> // 2008-03-18 03:53:42.949 test[51583:813] matchedString: 'is'

3.查找和替换，加括号和概念和Python中的一样，$1指代第一个括号中的内容

NSString *searchString = @"This is neat.";<br /> NSString *regexString = @"//b(//w+)//b";<br /> NSString *replaceWithString = @"{$1}";<br /> NSString *replacedString = NULL;<br /> replacedString = [searchString stringByReplacingOccurrencesOfRegex:regexString withString:replaceWithString];<br /> //NSMutableString可以直接替换，并返回替换的次数<br /> NSLog(@"replaced string: '%@'", replacedString);<br /> // 2008-07-01 19:03:03.195 test[68775:813] replaced string: '{This} {is} {neat}.'<br /> NSMutableString *mutableString = [NSMutableString stringWithString:@"This is neat."];<br /> NSString *regexString = @"//b(//w+)//b";<br /> NSString *replaceWithString = @"{$1}";<br /> NSUInteger replacedCount = 0UL;<br /> replacedCount = [mutableString replaceOccurrencesOfRegex:regexString withString:replaceWithString];<br /> NSLog(@"count: %lu string: '%@'", (u_long)replacedCount, mutableString);<br /> // 2008-07-01 21:25:43.433 test[69689:813] count: 3 string: '{This} {is} {neat}.'

4.用于拆分，返回一个拆分后的字符串数组

NSString *searchString = @"This is neat.";<br /> NSString *regexString = @"//s+";<br /> NSArray *splitArray = NULL;<br /> splitArray = [searchString componentsSeparatedByRegex:regexString];<br /> // splitArray == { @"This", @"is", @"neat." }<br /> NSLog(@"splitArray: %@", splitArray);

5.返回所有匹配的字符串数组，这个例子中虽然有多个括号，但是
componentsMatchedByRegex不管

NSString *searchString = @"$10.23, $1024.42, $3099";<br /> NSString *regexString = @"//$((//d+)(?://.(//d+)|//.?))";<br /> NSArray *matchArray = NULL;<br /> matchArray = [searchString componentsMatchedByRegex:regexString];<br /> // matchArray == { @"$10.23", @"$1024.42", @"$3099" };<br /> NSLog(@"matchArray: %@", matchArray);<br /> 6.返回所有匹配的字符串数组处理所有的括号<br /> NSString *searchString = @"$10.23, $1024.42, $3099";<br /> NSString *regexString = @"//$((//d+)(?://.(//d+)|//.?))";<br /> NSArray *capturesArray = NULL;<br /> capturesArray = [searchString arrayOfCaptureComponentsMatchedByRegex:regexString];<br /> /* capturesArray ==<br /> [NSArray arrayWithObjects:<br /> [NSArray arrayWithObjects: @"$10.23", @"10.23", @"10", @"23", NULL],<br /> [NSArray arrayWithObjects:@"$1024.42", @"1024.42", @"1024", @"42", NULL],<br /> [NSArray arrayWithObjects: @"$3099", @"3099", @"3099", @"", NULL],<br /> NULL];<br /> */<br /> NSLog(@"capturesArray: %@", capturesArray);<br /> 输出结果：<br /> shell% ./capturesArray↵<br /> 2009-05-06 03:25:46.852 capturesArray[69981:10b] capturesArray: (<br /> (<br /> "$10.23",<br /> "10.23",<br /> 10,<br /> 23<br /> ),<br /> (<br /> "$1024.42",<br /> "1024.42",<br /> 1024,<br /> 42<br /> ),<br /> (<br /> "$3099",<br /> 3099,<br /> 3099,<br /> ""<br /> )<br /> )