+ (nullable NSRegularExpression *)regularExpressionWithPattern:(NSString *)pattern options:(NSRegularExpressionOptions)options error:(NSError **)error;

- (nullable instancetype)initWithPattern:(NSString *)pattern options:(NSRegularExpressionOptions)options error:(NSError **)error

 typedef NS_OPTIONS(NSUInteger, NSRegularExpressionOptions) {
 NSRegularExpressionCaseInsensitive  = 1 << 0, //不區分大小寫的
 NSRegularExpressionAllowCommentsAndWhitespace = 1 << 1, //忽略空格和# -
 NSRegularExpressionIgnoreMetacharacters = 1 << 2, //整體化
 NSRegularExpressionDotMatchesLineSeparators = 1 << 3, //匹配任何字符，包括行分隔符
 NSRegularExpressionAnchorsMatchLines  = 1 << 4, //允許^和$在匹配的開始和結束行
 NSRegularExpressionUseUnixLineSeparators = 1 << 5, //(查找范圍為整個無效)
 NSRegularExpressionUseUnicodeWordBoundaries = 1 << 6 //(查找范圍為整個無效)
 };

//枚舉允許Block處理每個正則表達式匹配的字符串
- (void)enumerateMatchesInString:(NSString *)string options:(NSMatchingOptions)options range:(NSRange)range usingBlock:(void (NS_NOESCAPE ^)(NSTextCheckingResult * _Nullable result, NSMatchingFlags flags, BOOL *stop))block;

//返回一個數組，包含字符串中正則表達式的所有匹配項
- (NSArray<NSTextCheckingResult *> *)matchesInString:(NSString *)string options:(NSMatchingOptions)options range:(NSRange)range;

//返回字符串指定范圍內匹配數
- (NSUInteger)numberOfMatchesInString:(NSString *)string options:(NSMatchingOptions)options range:(NSRange)range;

//返回字符串指定范圍內第一個匹配項。
- (nullable NSTextCheckingResult *)firstMatchInString:(NSString *)string options:(NSMatchingOptions)options range:(NSRange)range;

//返回字符串指定范圍內第一個匹配的范圍
- (NSRange)rangeOfFirstMatchInString:(NSString *)string options:(NSMatchingOptions)options range:(NSRange)range;

typedef NS_OPTIONS(NSUInteger, NSMatchingOptions) {
 NSMatchingReportProgress   = 1 << 0,  /* 在長時間運行的匹配操作中定期調用Block */
 NSMatchingReportCompletion  = 1 << 1,  /* 完成任何匹配后，調用Block一次*/
 NSMatchingAnchored    = 1 << 2,  /*指定匹配僅限于搜索范圍開始時的匹配 */
 NSMatchingWithTransparentBounds = 1 << 3,  /* 定匹配可以檢查超出搜索范圍的范圍的字符串的部分，以用于諸如字邊界檢測，前瞻等。如果搜索范圍包含整個字符串，該常量將不起作用 */
 NSMatchingWithoutAnchoringBounds = 1 << 4  /* 指定^并且$不會自動匹配搜索范圍的開始和結束，但仍將與整個字符串的開頭和結尾相匹配。如果搜索范圍包含整個字符串，則該常量不起作用 */
};

//返回與模板字符串替換的匹配正則表達式的新字符串
- (NSString *)stringByReplacingMatchesInString:(NSString *)string options:(NSMatchingOptions)options range:(NSRange)range withTemplate:(NSString *)templ;

//返回替換的個數
- (NSUInteger)replaceMatchesInString:(NSMutableString *)string options:(NSMatchingOptions)options range:(NSRange)range withTemplate:(NSString *)templ;

//自定義替換功能
- (NSString *)replacementStringForResult:(NSTextCheckingResult *)result inString:(NSString *)string offset:(NSInteger)offset template:(NSString *)templ;

//通過根據需要添加反斜杠轉義來返回模板字符串，以保護符合模式元字符的任何字符
+ (NSString *)escapedTemplateForString:(NSString *)string;

 NSString *str = @"aabbcccdeaargdo14141214aaghfh66821d3gad4";
 NSRegularExpression *expression = [NSRegularExpression regularExpressionWithPattern:@"aa" options:NSRegularExpressionCaseInsensitive error:NULL];
 if (expression != nil) {
  //匹配到的第一組
  NSTextCheckingResult *firstMatch = [expression firstMatchInString:str options:NSMatchingReportProgress range:NSMakeRange(0, str.length)];
  NSRange range = [firstMatch rangeAtIndex:0];
  NSString *result = [str substringWithRange:range];
  NSLog(@"匹配到的第一組:%@",result);
  //匹配到的個數
  NSInteger number = [expression numberOfMatchesInString:str options:NSMatchingReportProgress range:NSMakeRange(0, str.length)];
  NSLog(@"匹配到的個數%ld",number);
  //配到到的所有數據
  NSArray *allMatch = [expression matchesInString:str options:NSMatchingReportProgress range:NSMakeRange(0, str.length)];
  for (int i = 0; i < allMatch.count; i ++) {
   NSTextCheckingResult *matchItem = allMatch[i];
   NSRange range = [matchItem rangeAtIndex:0];
   NSString *result = [str substringWithRange:range];
   NSLog(@"匹配到的數據:%@",result);
  }
  //匹配到第一組的位置
  NSRange firstRange = [expression rangeOfFirstMatchInString:str options:NSMatchingReportProgress range:NSMakeRange(0, str.length)];
  NSLog(@"匹配到第一組的位置:開始位置%lu--長度%lu",(unsigned long)firstRange.location,(unsigned long)firstRange.length);
  
  //替換字符串
  NSString *resultStr = [expression stringByReplacingMatchesInString:str options:NSMatchingReportProgress range:NSMakeRange(0, str.length) withTemplate:@"bbbb"];
  NSLog(@"替換后的字符串:%@",resultStr);
  
  NSInteger resultNum = [expression replaceMatchesInString:[str mutableCopy] options:NSMatchingReportProgress range:NSMakeRange(0, str.length) withTemplate:@"bbbb"];
  NSLog(@"替換的個數;%ld",(long)resultNum);
 }

打印log:
2017-08-13 23:28:53.898 NSRegularExpressionDemo[82046:8220904] 匹配到的第一組:aa
NSRegularExpressionDemo[82046:8220904] 匹配到的個數3
NSRegularExpressionDemo[82046:8220904] 匹配到的數據:aa
NSRegularExpressionDemo[82046:8220904] 匹配到的數據:aa
NSRegularExpressionDemo[82046:8220904] 匹配到的數據:aa
NSRegularExpressionDemo[82046:8220904] 匹配到第一組的位置:開始位置0--長度2
NSRegularExpressionDemo[82046:8220904] 替換后的字符串:bbbbbbcccdebbbbrgdo14141214bbbbghfh66821d3gad4
NSRegularExpressionDemo[82046:8220904] 替換的個數;3

//NSStringCompareOptions --> NSRegularExpressionSearch
- (NSRange)rangeOfString:(NSString *)searchString options:(NSStringCompareOptions)mask;
- (NSRange)rangeOfString:(NSString *)searchString options:(NSStringCompareOptions)mask range:(NSRange)rangeOfReceiverToSearch;
- (NSRange)rangeOfString:(NSString *)searchString options:(NSStringCompareOptions)mask range:(NSRange)rangeOfReceiverToSearch locale:(nullable NSLocale *)locale

 NSString *str = @"aabbcccdeaargdo14141214aaghfh66821d3gad4";
 NSRange strMatchStr = [str rangeOfString:@"aa" options:NSRegularExpressionSearch];
 NSLog(@"匹配到字符串的位置:開始位置%lu--長度%lu",(unsigned long)strMatchStr.location,(unsigned long)strMatchStr.length)
打印log:
NSRegularExpressionDemo[82080:8224265] 匹配到字符串的位置:開始位置0--長度2

 NSString *str2 = @"aabbcc";
 NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",@"^aa(.)*cc$"];
 BOOL isMatch = [predicate evaluateWithObject:str2];
 NSLog(@"匹配的結果:%d",isMatch);
打印log:
NSRegularExpressionDemo[82679:8253019] 匹配的結果:1