在代码开发过程中,我们经常需要用来校验邮箱、手机号等等,这个时候就需要用到正则表达式。在iOS开发中,能用来做正则校验的有两个 NSPredicate 和 NSRegularExpression 。
NSPredicate
NSPredicate 能用来简单做正则校验,但是它的问题是存在校验不出来的情况。
//NSString+RegEx.h #import <Foundation/Foundation.h> @interface NSString (RegEx) #pragma mark - NSPredicate - (BOOL)mars_matchedByPrdicateToRegEx:(NSString *)regEx; @end //NSString+RegEx.m #import "NSString+RegEx.h" @implementation NSString (RegEx) #pragma mark - NSPredicate - (BOOL)mars_matchedByPrdicateToRegEx:(NSString *)regEx{ NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regEx]; return [predicate evaluateWithObject:self]; } @end
NSRegularExpression (推荐)
NSRegularExpression 相对于 NSPredicate 功能就强大的多了,这也是iOS正则校验的正统路子。
//NSString+RegEx.h #import <Foundation/Foundation.h> @interface NSString (RegEx) #pragma mark - NSRegularExpression //校验是否匹配 - (BOOL)mars_matchedToRegEx:(NSString *)regEx; //匹配到的第一个字符串 - (NSString *)mars_firstMatchToRegEx:(NSString *)regEx; //所有匹配的字符串 - (NSArray *)mars_matchesToRegEx:(NSString *)regEx; //替换匹配到的字符串 - (NSString *)mars_stringByReplaceMatchesToRegEx:(NSString *)regEx replaceString:(NSString *)replaceString; @end //NSString+RegEx.m #import "NSString+RegEx.h" @implementation NSString (RegEx) #pragma mark - NSRegualrExpression //校验是否匹配 - (BOOL)mars_matchedToRegEx:(NSString *)regEx{ NSError *error; NSRegularExpression *regularExpression = [NSRegularExpression regularExpressionWithPattern:regEx options:NSRegularExpressionCaseInsensitive error:&error]; NSUInteger number = [regularExpression numberOfMatchesInString:self options:0 range:NSMakeRange(0, self.length)]; return number != 0; } //匹配到的第一个字符串 - (NSString *)mars_firstMatchToRegEx:(NSString *)regEx{ NSError *error; NSRegularExpression *regularExpression = [NSRegularExpression regularExpressionWithPattern:regEx options:NSRegularExpressionCaseInsensitive error:&error]; NSTextCheckingResult *firstMatch = [regularExpression firstMatchInString:self options:0 range:NSMakeRange(0, self.length)]; if (firstMatch) { NSString *result = [self substringWithRange:firstMatch.range]; return result; } return nil; } //所有匹配的字符串 - (NSArray *)mars_matchesToRegEx:(NSString *)regEx{ NSError *error; NSRegularExpression *regularExpression = [NSRegularExpression regularExpressionWithPattern:regEx options:NSRegularExpressionCaseInsensitive error:&error]; NSArray *matchArray = [regularExpression matchesInString:self options:0 range:NSMakeRange(0, self.length)]; NSMutableArray *array = [NSMutableArray array]; if (matchArray.count != 0) { for (NSTextCheckingResult *match in matchArray) { NSString *result = [self substringWithRange:match.range]; [array addObject:result]; } } return array; } //替换匹配到的字符串 - (NSString *)mars_stringByReplaceMatchesToRegEx:(NSString *)regEx replaceString:(NSString *)replaceString{ NSError *error; NSRegularExpression *regularExpression = [NSRegularExpression regularExpressionWithPattern:regEx options:NSRegularExpressionCaseInsensitive error:&error]; return [regularExpression stringByReplacingMatchesInString:self options:0 range:NSMakeRange(0, self.length) withTemplate:replaceString]; } @end
最后我们看到,还是推荐大家使用NSRegularExpression来做正则的校验,如果大家在学习中有更好的解决方法或者心得,可以在下方的留言区讨论。