Replace any string between quotes

Question

Problem:

Cannot find a consistent way to replace a random string between quotes with a specific string I want. Any help would be greatly appreciated.

Example:

String str1 = "test=\"-1\"";

should become

String str2 = "test=\"31\"";

but also work for

String str3 = "test=\"foobar\"";

basically I want to turn this

String str4 = "test=\"antyhingCanGoHere\"";

into this

String str4 = "test=\"31\"";

Have tried:

Case insensitive Regex without using RegexOptions enumeration

How do you do case-insensitive string replacement using regular expressions?

Replace any character in between AnyText: and <usernameredacted@example.com> with an empty string using Regex?

Replace string in between occurrences

Replace a String between two Strings

Current code:

    Regex RemoveName = new Regex("(?VARIABLE=\").*(?=\")", RegexOptions.IgnoreCase);
    String convertSeccons = RemoveName.Replace(ruleFixed, "31");

Returns error:

System.ArgumentException was caught
  Message=parsing "(?VARIABLE=").*(?=")" - Unrecognized grouping construct.
  Source=System
  StackTrace:
       at System.Text.RegularExpressions.RegexParser.ScanGroupOpen()
       at System.Text.RegularExpressions.RegexParser.ScanRegex()
       at System.Text.RegularExpressions.RegexParser.Parse(String re, RegexOptions op)
       at System.Text.RegularExpressions.Regex..ctor(String pattern, RegexOptions options, Boolean useCache)
       at System.Text.RegularExpressions.Regex..ctor(String pattern, RegexOptions options)
       at application.application.insertGroupID(String rule) in C:\Users\winserv8\Documents\Visual Studio 2010\Projects\application\application\MainFormLauncher.cs:line 298
       at application.application.xmlqueryDB(String xmlSaveLocation, TextWriter tw, String ruleName) in C:\Users\winserv8\Documents\Visual Studio 2010\Projects\application\application\MainFormLauncher.cs:line 250
  InnerException: 

found answer

string s = Regex.Replace(ruleFixed, "VARIABLE=\"(.*)\"", "VARIABLE=\"31\"");
ruleFixed = s;

I found this code sample at Replace any character in between AnyText: and with an empty string using Regex? which is one of the links i previously posted and just had skipped over this syntax because i thought it wouldnt handle what i needed.

Answer 1

var str1 = "test=\"foobar\"";
var str2 = str1.Substring(0, str1.IndexOf("\"") + 1) + "31\"";

If needed add check for IndexOf != -1

Answer 2

I don't know if I understood you correct, but if you want to replace all chars inside string, why aren't you using simple regular expresission

String str = "test=\"-\"1\"";

Regex regExpr = new Regex("\".*\"", RegexOptions.IgnoreCase);
String result = regExpr.Replace(str , "\"31\"");

Console.WriteLine(result);

prints:

test="31"

Note: You can take advantage of plain old XAttribute

String ruleFixed = "test=\"-\"1\"";

var splited = ruleFixed.Split('=');
var attribute = new XAttribute(splited[0], splited[1]);

attribute.Value = "31";

Console.WriteLine(attribute);//prints test="31"

Answer 3

In the case that your string has other things in it besides just the key/value pair of key="value", then you need to make the value-match part not match quote marks, or it will match all the way from the first value to the last quote mark in the string.

If that is true, then try this:

Regex.Replace(ruleFixed, "(?<=VARIABLE\s*=\s*\")[^\"]*(?=\")", "31");

This uses negative look-behind to match the VARIABLE=" part (with optional white space around it so VARIABLE = " would work as well, and negative look-ahead to match the ending ", without including the look-ahead/behind in the final match, enabling you to just replace the value you want.

If not, then your solution will work, but is not optimal because you have to repeat the value and the quote marks in the replace text.

Answer 4

var parts = given.Split('=');
return string.Format("{0}=\"{1}\"", parts[0], replacement);

Answer 5

Assuming that the string within the quotes does not contain quotes itself, you can use this general pattern in order to find a position between a prefix and a suffix:

(?<=prefix)find(?=suffix)

In your case

(?<=\w+=").*?(?=")

Here we are using the prefix \w+=" where \w+ denotes word characters (the variable) and =" are the equal sign and the quote.

We want to find anything .*? until we encounter the next quote.

The suffix is simply the quote ".

string result = Regex.Replace(input, "(?<=\\w+=\").*?(?=\")", replacement);

Answer 6

Try this:

[^"\r\n]*(?:""[\r\n]*)*

Answer 7

     String str1 = "test=\"-1\"";
     string res = Regex.Replace(str1, "(^+\").+(\"+)", "$1" + "31" + "$2");

Answer 8

var pattern = "\"(.*)?\"";
var regex = new Regex(pattern, RegexOptions.IgnoreCase);
var replacement = regex.Replace("test=\"hereissomething\"", "\"31\"");

Answer 9

string s = Regex.Replace(ruleFixed, "VARIABLE=\"(.*)\"", "VARIABLE=\"31\"");
ruleFixed = s;

I found this code sample at Replace any character in between AnyText: and <usernameredacted@example.com> with an empty string using Regex? which is one of the links i previously posted and just had skipped over this syntax because i thought it wouldnt handle what i needed.

Answer 10

String str1 = "test=\"-1\"";
string[] parts = str1.Split(new[] {'"'}, 3);
string str2 = parts.Length == 3 ? string.Join(@"\", parts.First(), "31", parts.Last()) : str1;

Answer 11

Im pretty bad at RegEx but you could make a simple ExtensionMethod using string functions to do this.

public static class StringExtensions
{
    public static string ReplaceBetweenQuotes(this string str, string replacement)
    {
        if (str.Count(c => c.Equals('"')) == 2)
        {
            int start = str.IndexOf('"') + 1;
            str = str.Replace(str.Substring(start, str.LastIndexOf('"') - start), replacement);
        }
        return str;
    }
}

Usage:

 String str3 = "test=\"foobar\"";
 str3 = str3.ReplaceBetweenQuotes("31");

returns: "test=\"31\""