Regex match and replace operators in math operation

Question

Given an input string ``` 12/3 12*3/12 (12*54)/(3/4) ``` I need to find and replace each operator with a string that contains the operator ``` some12text/some3text some12text*some2text/some12text (some12text*some54text)/(some3text/some4text) ``` practical application: From a backend (c#), i have the following string ``` 34*157 ``` which i need to translate to: ``` document.getElementById("34").value*document.getElementById("157").value ``` and returned to the screen which can be run in an eval() function. So far I have ``` var pattern = @"\d+"; var input = "12/3; Regex r = new Regex(pattern); var matches = r.Matches(input); foreach (Match match in matches) { // im at a loss what to match and replace here } ``` Caution: i cannot do a blanket input.Replace() in the foreach loop, as it may incorrectly replace (12/123) - it should only match the first 12 to replace Caution2: I can use string.Remove and string.Insert, but that mutates the string after the first match, so it throws off the…

Accepted Answer

Here you go

```
string pattern = @"\d+"; //machtes 1-n consecutive digits
var input = "(12*54)/(3/4)";
string result = Regex.Replace(input, pattern, "some$0Text"); 
```

`$0` is the character group matching the pattern `\d+`. You can also write

```
string result = Regex.Replace(input, pattern, m => "some"+ m.Groups[0]+ "Text"); 
```

Fiddle: https://dotnetfiddle.net/JUknx2

Regex match and replace operators in math operation

Solution

Problem