C＃替换正则表达式 [英] C# Replace with regex

问题描述

我是新的VB，C＃，和我与正则表达式挣扎。我想我已经得到了下面的代码格式来取代正则表达式匹配，在我的文件空格

编辑：每评论评论这个代码块已被更改

  VAR fileContents = System.IO.File.ReadAllText（@C：\path\to\file.csv） ; 
  

fileContents = fileContents.Replace（fileContents，@正则表达式，）;

 正则表达式=新的正则表达式（模式）; 
 regex.Replace（filecontents，）; 
 System.IO.File.WriteAllText（@C：\path\to\file.csv，fileContents）; 
  

我的文件的格式是这样的：

 1111111，22222222222，文本可能，有一个逗号，或者二，2014年9月1日,,,,,, 
  

到目前为止，我正则表达式找到和包含一个逗号（有没有在第一个或最后一个单元格逗号，所以我不担心不包括两项。我在的快报

 （小于？=）（[^] +，[^] +）。（？=，）
  

我只是不知道如何处理逗号作为隔离需要更换的东西。什么是做到这一点的最好方法是什么？

解决：
合并[^] +背后/提前看：

 （小于=[ ^] +）（，）（？= [^] +）
  

最后编辑：
这里是我最后的完整的解决方案：

  //读取文件内容
 VAR fileContents = System.IO .File.ReadAllText（@C：\path\to\file.csv）; 
 
 //找到双引号
变种的regex =新的正则表达式（之间的所有逗号（小于？=，\）（[^ \] + [^ \ ] +（= \？））; 
 
 //与替换所有的逗号，
 fileContents = regex.Replace（fileContents，M => m.ToString（ ）.Replace（，））; 
 
 //结果写入回文件
 System.IO.File.WriteAllText（@C：\path\to \file.csv，fileContents）; 
  

解决方案

我可能会使用Regex.Replace的，需要一个代表超载返还替换文本。当你有一个简单的正则表达式来识别模式
这是有用的，但你需要做的东西少直接的（复杂的逻辑）更换。

我觉得让你的正则表达式简单的将支付的好处，当你试图以后维护。

注意：这是类似于@Florian答案，但这种替换限制自己只更换了匹配的文本

 串EXP =（小于？=，\）（[^ \] +，[^ \] +）（= \？，）; 
变种的regex =新的正则表达式（EXP）; 
串replacedtext = regex.Replace（filecontents，M =方式> m.ToString（）更换（，））
  

I'm new to VB, C#, and am struggling with regex. I think I've got the following code format to replace the regex match with blank space in my file.

EDIT: Per comments this code block has been changed.

var fileContents = System.IO.File.ReadAllText(@"C:\path\to\file.csv");

fileContents = fileContents.Replace(fileContents, @"regex", "");

regex = new Regex(pattern);
regex.Replace(filecontents, "");
System.IO.File.WriteAllText(@"C:\path\to\file.csv", fileContents);

My files are formatted like this:

"1111111","22222222222","Text that may, have a comma, or two","2014-09-01",,,,,,

So far, I have regex finding any string between ," and ", that contains a comma (there are never commas in the first or last cell, so I'm not worried about excluding those two. I'm testing regex in Expresso

(?<=,")([^"]+,[^"]+)(?=",)

I'm just not sure how to isolate that comma as what needs to be replaced. What would be the best way to do this?

SOLVED: Combined [^"]+ with look behind/ahead:

(?<=,"[^"]+)(,)(?=[^"]+",)

FINAL EDIT: Here's my final complete solution:

//read file contents
var fileContents = System.IO.File.ReadAllText(@"C:\path\to\file.csv");

//find all commas between double quotes
var regex = new Regex("(?<=,\")([^\"]+,[^\"]+(?=\",)");

//replace all commas with ""
fileContents = regex.Replace(fileContents, m => m.ToString().Replace(",", ""));

//write result back to file
System.IO.File.WriteAllText(@"C:\path\to\file.csv", fileContents);

解决方案

I would probably use the overload of Regex.Replace that takes a delegate to return the replaced text. This is useful when you have a simple regex to identify the pattern but you need to do something less straightforward (complex logic) for the replace.

I find keeping your regexes simple will pay benefits when you're trying to maintain them later.

Note: this is similar to the answer by @Florian, but this replace restricts itself to replacement only in the matched text.

string exp = "(?<=,\")([^\"]+,[^\"]+)(?=\",)";
var regex = new Regex(exp); 
string replacedtext = regex.Replace(filecontents, m => m.ToString().Replace(",",""))

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