常用的正则表达式
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:
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。