NSScanner vs.componentsSeparatedByString [英] NSScanner vs. componentsSeparatedByString

问题描述

我有一个大文本文件(大约10 MB).在文本文件中，有一些类似的值(行之间没有空行，我在这里无法正确设置其格式):

I have a large text file (about 10 MB). In the text file there are values like (without the empty lines between the rows, I couldn't format it here properly):

;string1;stringValue1;

;string2;stringValue2;

;string3;stringValue3;

;string4;stringValue4;

我正在使用一个非常丑陋的解决方案将所有'stringX'值解析为一个数组，并将'stringValueX'解析为另一个字符串:

I'm parsing all the 'stringX' values to an Array and the 'stringValueX' to another string, using a pretty ugly solution:

  words = [rawText componentsSeparatedByString:@";"];
  NSEnumerator *word = [words objectEnumerator];

  while(tmpWord = [word nextObject]) {

   if ([tmpWord isEqualToString: @""] || [tmpWord isEqualToString: @"\r\n"] || [tmpWord isEqualToString: @"\n"]) {
    //   NSLog(@"%@*** NOTHING *** ",tmpWord);

   }else { // here I add tmpWord the arrays...

我已尝试通过以下示例使用 NSScanner 进行此操作:

I've tried to do this using NSScanner by following this example: http://www.macresearch.org/cocoa-scientists-part-xxvi-parsing-csv-data

但是我收到了内存警告，然后全部崩溃了.

But I received memory warnings and then it all crashed.

我可以使用 NSScanner 进行此操作吗?如果可以，那么任何人都可以给我一个如何执行此操作的示例吗?

Shall I do this using NSScanner and if so, can anyone give me an example of how to do that?

谢谢！

推荐答案

在大多数情况下， NSScanner 比 componentsSeparatedByString:更适合，尤其是在尝试保留内存的情况下

In most cases NSScanner is better suited than componentsSeparatedByString:, especially if you are trying to preserve memory.

您的文件可以通过这样的循环进行解析:

Your file could be parsed by a loop like this:

while (![scanner isAtEnd]) {
   NSString *firstPart = @"";
   NSString *secondPart = @"";

   [scanner scanString: @";" intoString: NULL];
   [scanner scanUpToString: @";" intoString: &firstPart];

   [scanner scanString: @";" intoString: NULL];
   [scanner scanUpToString: @";" intoString: &secondPart];

   [scanner scanString: @";" intoString: NULL];

   // TODO: add firstPart and secondPart to your arrays
}

您可能需要为此添加错误检查代码，以防文件无效.

You probably need to add error-checking code to this in case you get an invalid file.

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