(轉)iOS中3種Regex的使用與比較,iosRegex
1.利用NSPredicate(謂詞)匹配例如匹配有效郵箱:NSString *email = @“nijino_saki@163.com”; NSString *regex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}"; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex]; BOOL isValid = [predicate evaluateWithObject:email];謂詞匹配比較靈活,但是需要有謂詞的相關知識。2.利用rangeOfString:option:直接尋找 NSString *searchText = @"// Do any additional setup after loading the view, typically from a nib."; NSRange range = [searchText rangeOfString:@"(?:[^,])*\\." options:NSRegularExpressionSearch]; if (range.location != NSNotFound) { NSLog(@"%@", [searchText substringWithRange:range]); }options中設定NSRegularExpressionSearch就是表示利用Regex匹配,會返回第一個匹配結果的位置。3.使用Regex類 NSString *searchText = @"// Do any additional setup after loading the view, typically from a nib."; NSError *error = NULL; NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(?:[^,])*\\." options:NSRegularExpressionCaseInsensitive error:&error]; NSTextCheckingResult *result = [regex firstMatchInString:searchText options:0 range:NSMakeRange(0, [searchText length])]; if (result) { NSLog(@"%@\n", [searchText substringWithRange:result.range]); }使用系統的Regex類(NSRegularExpression)會返回匹配的多個結果。小結:第一種匹配需要學習NSPredicate的寫法,需要查閱蘋果相關技術文檔;如果只關心第一個匹配的結果,第二種匹配較為簡潔;如果需要匹配多個結果,同時匹配多次,第三種方式效率會更高。