ios 正则表达式

iOS 中可以通过 NSPredicate 来处理正则表达式。相关资料如下：

NSPredicate 苹果官方文档：

http://developer.apple.com/documentation/Cocoa/Conceptual/Predicates/predicates.html

Predicate format strings：

http://developer.apple.com/documentation/Cocoa/Conceptual/Predicates/Articles/pSyntax.html

ICU 正则表达式规则：

http://www.icu-project.org/userguide/regexp.html

在 iOS 中，我们使用 NSPredicate 的字符串比较功能来进行正则表达式处理，其比较关键字为：

MATCHES

下面，列举一个匹配6-15个由字母/数字组成的字符串的正则表达式，来看看 NSPredicate 的具体使用：

[cpp] view
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NSString * regex = @"(^[A-Za-z0-9]{6,15}$)";

NSPredicate * pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];

BOOL isMatch = [pred evaluateWithObject:@"123456ABCde"];

下面是一些常用的正则表达式

//邮箱

+ (BOOL) validateEmail:(NSString *)email

{

NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";

NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];

return [emailTest evaluateWithObject:email];

}

//手机号码验证

+ (BOOL) validateMobile:(NSString *)mobile

{

//手机号以13， 15，18开头，八个 \d 数字字符

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];

}

//车牌号验证

+ (BOOL) validateCarNo:(NSString *)carNo

{

NSString *carRegex = @"^[\u4e00-\u9fa5]{1}[a-zA-Z]{1}[a-zA-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];

}

//车型

+ (BOOL) validateCarType:(NSString *)CarType

{

NSString *CarTypeRegex = @"^[\u4E00-\u9FFF]+$";

NSPredicate *carTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",CarTypeRegex];

return [carTest evaluateWithObject:CarType];

}

//用户名

+ (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;

}

//密码

+ (BOOL) validatePassword:(NSString *)passWord

{

NSString *passWordRegex = @"^[a-zA-Z0-9]{6,20}+$";

NSPredicate *passWordPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",passWordRegex];

return [passWordPredicate evaluateWithObject:passWord];

}

//昵称

+ (BOOL) validateNickname:(NSString *)nickname

{

NSString *nicknameRegex = @"^[\u4e00-\u9fa5]{4,8}$";

NSPredicate *passWordPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",nicknameRegex];

return [passWordPredicate evaluateWithObject:nickname];

}

//身份证号

+ (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];

}

其实iOS中有三种方式来实现正则表达式的匹配。现在将他们都记录在这里：

1.利用NSPredicate（谓词）匹配

例如匹配有效邮箱：

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];

谓词匹配比较灵活，但是需要有谓词的相关知识。

2.利用rangeOfString：option：直接查找

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中设定NSRegularExpressionSearch就是表示利用正则表达式匹配，会返回第一个匹配结果的位置。

3.使用正则表达式类

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]);

}

使用系统的正则表达式类（NSRegularExpression）会返回匹配的多个结果。

小结：

第一种匹配需要学习NSPredicate的写法，需要查阅苹果相关技术文档；如果只关心第一个匹配的结果，第二种匹配较为简洁；如果需要匹配多个结果，同时匹配多次，第三种方式效率会更高。