Common Regular Expressions

In IOS, we use the string comparison feature of nspredicate for regular expression processing with the following keywords:MATCHES

Here's a regular expression that matches 6-15 letters/numbers, to see how nspredicate is used:

    NSString * Regex        = @ "(^[a-za-z0-9]{6,15}$)";      Nspredicate * pred      = [Nspredicate predicatewithformat:@ "Self MATCHES%@", regex];      BOOL IsMatch            = [pred evaluatewithobject:@ "123456ABCde"];  

Here are some common regular expressions//mailbox + (BOOL) Validateemail: (NSString *) Email {nsstring *emailregex = @ "[a-z0-9a-z._%+-][email p Rotected][a-za-z0-9.-]+\\. [A-za-z]      {2,4} ";      Nspredicate *emailtest = [Nspredicate predicatewithformat:@ "Self MATCHES%@", Emailregex];  return [Emailtest Evaluatewithobject:email];  }//Mobile number verification + (BOOL) Validatemobile: (NSString *) Mobile {//Mobile phone number starts with 13, 15, 18, eight \d numeric characters nsstring *phoneregex = @ "^ ((13[0-9]) | (15[^4,\\d]) | (18[0,0-9]))      \\d{8}$ ";      Nspredicate *phonetest = [Nspredicate predicatewithformat:@ "Self MATCHES%@", Phoneregex];  return [Phonetest Evaluatewithobject:mobile]; }//Vehicle grade verification + (BOOL) Validatecarno: (NSString *) Carno {nsstring *carregex = @ "^[\u4e00-\u9fa5]{1}[a-za-z]{1}[a-z      A-z_0-9]{4}[a-za-z_0-9_\u4e00-\u9fa5]$ ";      Nspredicate *cartest = [Nspredicate predicatewithformat:@ "Self MATCHES%@", Carregex];      NSLog (@ "Cartest is%@", cartest);  return [Cartest Evaluatewithobject:carno]; }//Model + (BOOL) validAtecartype: (NSString *) Cartype {nsstring *cartyperegex = @ "^[\u4e00-\u9fff]+$";      Nspredicate *cartest = [Nspredicate predicatewithformat:@ "Self MATCHES%@", Cartyperegex];  return [Cartest Evaluatewithobject:cartype];      }//user name + (BOOL) Validateusername: (NSString *) name {NSString *usernameregex = @ "^[a-za-z0-9]{6,20}+$";      Nspredicate *usernamepredicate = [Nspredicate predicatewithformat:@ "Self MATCHES%@", Usernameregex];      BOOL B = [Usernamepredicate evaluatewithobject:name];  return B;      }//Password + (BOOL) ValidatePassword: (NSString *) PassWord {nsstring *passwordregex = @ "^[a-za-z0-9]{6,20}+$";      Nspredicate *passwordpredicate = [Nspredicate predicatewithformat:@ "Self MATCHES%@", Passwordregex];  return [Passwordpredicate Evaluatewithobject:password];      }//Nickname + (BOOL) Validatenickname: (NSString *) Nickname {NSString *nicknameregex = @ "^[\u4e00-\u9fa5]{4,8}$"; Nspredicate *passwordpredicate = [Nspredicate Predicatewithformat:@ "Self MATCHES%@", Nicknameregex];  return [Passwordpredicate Evaluatewithobject:nickname];      }//Social Security number + (BOOL) Validateidentitycard: (NSString *) Identitycard {BOOL flag;          if (identitycard.length <= 0) {flag = NO;      return flag; } nsstring *regex2 = @ "^ (\\d{14}|\\d{17}) (\\d|[      XX]) $ ";      Nspredicate *identitycardpredicate = [Nspredicate predicatewithformat:@ "Self MATCHES%@", Regex2];  return [Identitycardpredicate Evaluatewithobject:identitycard];   }

In fact, there are three ways to match regular expressions in iOS. Now put them all on the record here:

1. Using nspredicate (predicate) matching

For example, to match a valid mailbox:

NSString *email = @ "[email protected]";

NSString *regex = @ "[A-z0-9a-z._%+-][email protected][a-za-z0-9.-]+\\. [A-za-z] {2,4} ";

Nspredicate *predicate = [Nspredicate predicatewithformat:@ "Self MATCHES%@", regex];

BOOL isValid = [predicate evaluatewithobject:email];

predicate matching is more flexible, but requires knowledge of predicates.

2. Using rangeofstring:option: Direct lookup

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]);

}

The set nsregularexpressionsearch in options means that a regular expression match is used to return the position of the first matching result.

3. Using the Regular expression class

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]);

}

Using the system's regular expression class (Nsregularexpression) returns multiple results that match.

Summary:

The first match needs to learn Nspredicate's writing, need to consult Apple related technical documents; If you only care about the results of the first match, the second match is more concise; If you need to match multiple results and match them multiple times, the third way is more efficient.

Common Regular Expressions