Objective-C中利用正则去除非数字字母汉字方法实例

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UITextField *input;
@property (weak, nonatomic) IBOutlet UILabel *label;
@end
@implementation ViewController
- (void)viewDidLoad {
 [super viewDidLoad];
 self.input.delegate = self;
 [self.input addTarget:self action:@selector(textChange:) forControlEvents:UIControlEventEditingChanged];
}
//当文本内容改变时调用
- (void)textChange:(UITextField *)textField
{
 //这里调用相关方法过滤字符串显示出来
 self.label.text = //...;
}

- (NSString *)filterString1:(NSString *)str {
 NSString *regex = @"^[a-zA-Z0-9\u4e00-\u9fa5]+";
 NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
 NSMutableString * retStr = [NSMutableString string];
 for(NSInteger i=0; i<[str length];i++){
  NSRange range = NSMakeRange(i, 1);
  NSString *character = [str substringWithRange:range];
  if([pred evaluateWithObject:character])
  {
   [retStr appendString:character];
  }
 }
 return retStr;
}

//方案2
- (NSString *)filterString2:(NSString *)str {
 NSString *regex = @"[^a-zA-Z0-9\u4e00-\u9fa5]";
 NSMutableString *mstr = [NSMutableString stringWithFormat:@"%@", str];
 NSUInteger i = [mstr replaceOccurrencesOfString:regex withString:@"" options:NSRegularExpressionSearch range:NSMakeRange(0, mstr.length)];
 return [NSString stringWithFormat:@"%@-长度:%zd",mstr,i];
}

//方案3
- (NSString *)filterString3:(NSString *)str {
 NSString *regex = @"[^a-zA-Z0-9\u4e00-\u9fa5]";
 return [str stringByReplacingOccurrencesOfString:regex withString:@"" options:NSRegularExpressionSearch range:NSMakeRange(0, str.length)];
}