有没有办法计算NSString的行数？

Question

可能重复:
如何计算Objective-C字符串(NSString)中的行数？

有没有办法计算NSString的行数？

NSString * myString = @"line 1 \n line 2 \n";

lines = 3;

谢谢

Answer 1

当心componentsSeparatedByString是不是足够聪明的MAC /窗/ Unix行结尾之间检测.分离\n将适用于windows/unix行结尾,但不适用于经典的mac文件(并且有一些流行的mac编辑器默认仍然使用这些).你真的应该检查\r\n和\r.

另外,componentsSeparatedByString:是慢,内存饥饿.如果您关心性能,则应重复搜索换行并计算结果数:

NSString * myString = @"line 1 \n line 2 \n";

int lineCount = 1;
NSUInteger characterLocation = 0;
NSCharacterSet *newlineCharacterSet = [NSCharacterSet newlineCharacterSet];
while (characterLocation < myString.length) {
  characterLocation = [myString rangeOfCharacterFromSet:newlineCharacterSet options:NSLiteralSearch range:NSMakeRange(characterLocation, (myString.length - characterLocation))].location;

  if (characterLocation == NSNotFound) {
    break;
  }

  // if we are at a \r character and the next character is a \n, skip the next character
  if (myString.length >= characterLocation &&
      [myString characterAtIndex:characterLocation] == '\r' &&
      [myString characterAtIndex:characterLocation + 1] == '\n') {
    characterLocation++;
  }

  lineCount++;
  characterLocation++;
}

NSLog(@"%i", lineCount);