objective-c - 如何删除目标C中'>'之前和空格之后的内容？

Question

这是示例：

<aNodeName thsisjijdsnjdnjsd>, 我想删除thsisjijdsnjdnjsd,

如何检测空格之前>和之后的字符串，并在目标 C 中将其修剪掉？另外，请提醒我不知道aNodeNameor thsisjijdsnjdnjsd，因为数据可能会变成这样：

<anotherNodeName zxzxxzxzxz>, 我需要删除zxzxxzxzxz.

Answer 1

基本上你有两个选择

• 常用表达

  NSString *string = @"<aNodee thsisjijdsnjdnjsd>";
  NSError *error;
  NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"<(\\S+)( .*)>" options:NSRegularExpressionCaseInsensitive
                                                                           error:&error];
  NSArray *matches = [regex matchesInString:string options:0 range:NSMakeRange(0, [string length])];
  [matches enumerateObjectsUsingBlock:^(NSTextCheckingResult *result, NSUInteger idx, BOOL *stop) {
      NSString* nodeName = [string substringWithRange:[result rangeAtIndex:1]];
      NSString* value = [string substringWithRange:[result rangeAtIndex:2]];
      NSLog(@"%@ %@",nodeName, value);
  }];
  

  请注意，您不应该使用正则表达式解析复杂的 html。

• NSScanner

  NSScanner *scanner = [NSScanner scannerWithString:string];
  BOOL recordingValue = NO;
  
  NSMutableString *valueString = [@"" mutableCopy];
  [scanner setScanLocation:0];
  while (![scanner isAtEnd]) {
  
      NSString *charAtlocation = [string substringWithRange:NSMakeRange([scanner scanLocation], 1)];
      if ([charAtlocation isEqualToString:@" "]){
          recordingValue = YES;
          [valueString appendString:@" "];
      } else{
          if ([charAtlocation isEqualToString:@">"]){
              recordingValue = NO;
          } else if (recordingValue) {
              [valueString appendString:charAtlocation];
          }
      }
      [scanner setScanLocation:[scanner scanLocation]+1];
  } ;
  
  
  NSLog(@"Scanner approach: %@", valueString);
  NSLog(@"Scanner approach: %@", [string stringByReplacingOccurrencesOfString:valueString withString:@""]);
  

---

完整的基于命令行的示例

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[])
{

    @autoreleasepool {
        NSString *string = @"<aNodee thsisjijdsnjdnjsd> ";
        NSError *error;
        NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"<([a-zA-z]+)( .*)>" options:NSRegularExpressionCaseInsensitive
                                                                                 error:&error];
        NSArray *matches = [regex matchesInString:string options:0 range:NSMakeRange(0, [string length])];
        [matches enumerateObjectsUsingBlock:^(NSTextCheckingResult *result, NSUInteger idx, BOOL *stop) {
            NSString* nodeName = [string substringWithRange:[result rangeAtIndex:1]];
            NSString* value = [string substringWithRange:[result rangeAtIndex:2]];
            NSLog(@"Regex approach: %@ %@",nodeName, value);

            NSLog(@"Regex approach: %@", [string stringByReplacingOccurrencesOfString:value withString:@""]);
        }];




        NSScanner *scanner = [NSScanner scannerWithString:string];
        BOOL recordingValue = NO;

        NSMutableString *valueString = [@"" mutableCopy];
        [scanner setScanLocation:0];
        while (![scanner isAtEnd]) {

            NSString *charAtlocation = [string substringWithRange:NSMakeRange([scanner scanLocation], 1)];
            if ([charAtlocation isEqualToString:@" "]){
                recordingValue = YES;
                [valueString appendString:@" "];
            } else{
                if ([charAtlocation isEqualToString:@">"]){
                    recordingValue = NO;
                } else if (recordingValue) {
                    [valueString appendString:charAtlocation];
                }
            }
            [scanner setScanLocation:[scanner scanLocation]+1];
        } ;


        NSLog(@"Scanner approach: %@", valueString);
        NSLog(@"Scanner approach: %@", [string stringByReplacingOccurrencesOfString:valueString withString:@""]);
    }
    return 0;
}

输出：

Regex approach: aNodee  thsisjijdsnjdnjsd
Regex approach: <aNodee> 
Scanner approach:  thsisjijdsnjdnjsd
Scanner approach: <aNodee>