[英]Replace multiple Regex Matches each with a different replacement
I have a string that may or may not have multiple matches for a designated pattern. 我有一个字符串,可能有或没有指定模式的多个匹配。
Each needs to be replaced. 每个都需要更换。
I have this code: 我有这个代码:
var pattern = @"\$\$\@[a-zA-Z0-9_]*\b";
var stringVariableMatches = Regex.Matches(strValue, pattern);
var sb = new StringBuilder(strValue);
foreach (Match stringVarMatch in stringVariableMatches)
{
var stringReplacment = variablesDictionary[stringVarMatch.Value];
sb.Remove(stringVarMatch.Index, stringVarMatch.Length)
.Insert(stringVarMatch.Index, stringReplacment);
}
return sb.ToString();
The problem is that when I have several matches the first is replaced and the starting index of the other is changed so that in some cases after the replacement when the string is shorten I get an index out of bounds.. 问题是,当我有几个匹配时,第一个被替换,另一个的起始索引被改变,所以在某些情况下,当字符串缩短时,我得到一个超出范围的索引。
I know I could just use Regex.Replace
for each match but this sound performance heavy and wanted to see if someone could point a different solution to substitute multiple matches each with a different string. 我知道我可以为每场比赛使用
Regex.Replace
,但这个声音表现很重,并希望看看是否有人可以指出一个不同的解决方案,用不同的字符串替换多个匹配。
Use a Match evaluator inside the Regex.Replace
: 在
Regex.Replace
使用Match评估器:
var pattern = @"\$\$\@[a-zA-Z0-9_]*\b";
var stringVariableMatches = Regex.Replace(strValue, pattern,
m => variablesDictionary[m.Value]);
The Regex.Replace
method will perform global replacements, ie will search for all non-overlapping substrings that match the indicated pattern, and will replace each found match value with the variablesDictionary[m.Value]
. Regex.Replace
方法将执行全局替换,即将搜索与指示模式匹配的所有非重叠子串,并将使用variablesDictionary[m.Value]
替换每个找到的匹配值。
Note that it might be a good idea to check if the key exists in the dictionary . 请注意, 检查字典中是否存在密钥可能是个好主意。
using System;
using System.IO;
using System.Text.RegularExpressions;
using System.Collections.Generic;
using System.Linq;
public class Test
{
public static void Main()
{
var variablesDictionary = new Dictionary<string, string>();
variablesDictionary.Add("$$@Key", "Value");
var pattern = @"\$\$@[a-zA-Z0-9_]+\b";
var stringVariableMatches = Regex.Replace("$$@Unknown and $$@Key", pattern,
m => variablesDictionary.ContainsKey(m.Value) ? variablesDictionary[m.Value] : m.Value);
Console.WriteLine(stringVariableMatches);
}
}
Output: $$@Unknown and Value
. 输出:
$$@Unknown and Value
。
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