在 2 个字符串之间查找字符串并替换 - 正则表达式

Question

I have a string that I would like to find within it all the words between Description and and replace the words so that they are just 255 characters long. If the words are less than 255 characters it does nothing, if it is more than 255 characters it is to truncate the words. I used a regular expression, only words are caught outside the range defined by me.

I am the folowing regular expression:

(?<=<Name>Description<\/Name><Value>)(?<Text>.{0,255}).*?(?=<\/Value>)

The code is C#.

I have a C# script that does the folowing:

            string strFile = File.ReadAllText(@"D:\FINAL.xml");
            string pattern = @"(?<=<Name>Description<\/Name><Value>)(?<Text>.{0,255}).*?(?=<\/Value>)";
            string result = Regex.Replace(strFile, pattern, "${Text}");
            File.WriteAllText(@"D:\FINAL.xml", result);

For example: https://regex101.com/r/Etfpol/5

Answer 1

It is a bad idea, but your idea, your pc, ... (in general you shouldn't use Regexes to "parse" xml or html, bad things could happen/will happen, perhaps not today but tomorrow or the day after)

string pattern = @"(?<=<Name>Description</Name><Value>)([^<]*)(?=</Value>)";
const int maxLength = 255
string result = Regex.Replace(strFile, pattern, x => x.Value.Length > maxLength ? x.Value.Remove(maxLength) : x.Value);

You need a MatchEvaluator , a method that receives the match and calculates a replacement.

Mmmh... You can even do without a MatchEvaluator ...

string pattern = @"(?<=<Name>Description</Name><Value>)([^<]{0,255})([^<]*)(?=</Value>)";
string result = Regex.Replace(strFile, pattern, "$1");