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。
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//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
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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。
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//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
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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。