Replacing characters between two characters

Question

I'm trying to manipulate a string and I want to remove some characters in it.

Example scenario:

abc-def-c?p=2&x=5&z=6

I want to replace all chars starting from p and ending with the char after next & or ? with empty chars. Deleting them in a way.

Input: abc-def-c?p=2&x=5&z=6

Output: abc-def-c?x=5&z=6

I know I can achieve this with Substring ,IndexOf and Replace but sadly there is a problem that p,x,y parts may not be in this order all the time. I need something which would find just the part and replace it.

My regex skills are not that great so any help is appreciated.

@john - that is PERL ones that ARE different (because it is a trendy ninja scripting language). .Net uses the standard syntax, same as the vast majority of places that support Regex..... the / characters denote that this IS a regex, its like quotes round strings... you wouldn't say that Strings are different if the quotes that start and end them are different... i hope? — Milney, Apr 26 '17 at 15:03

Dmitry Egorov · Accepted Answer · 2017-04-26T14:55:51.500

2

Try this regex:

(?<=[?&])p=.*?(?:&|$)

It matches p= preceded by ? or & ((?<=[?&])) and followed by a string value which terminates with either & or end of string ((?:&|$))

Demo

edited Apr 26 '17 at 14:55

answered Apr 26 '17 at 14:53

Dmitry Egorov

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Looks great, how can I make it include the next & char too? – Ege Bayrak Apr 26 '17 at 14:55
@EgeBayrak you probably want the previous & char not the next one. – thinklarge Apr 26 '17 at 15:01

score 0 · Answer 2 · edited May 23 '17 at 12:10

0

I do not like Regexs so as an alternative if you are the same, you could use the class posted in one of the answers to this question;

Get url parameters from a string in .NET

Which turns Query String into a Dictionary, and then just take all keys except the one you want to ignore...

edited May 23 '17 at 12:10

Community

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answered Apr 26 '17 at 14:53

Milney

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score 0 · Answer 3 · edited Apr 26 '17 at 15:26

check input contains of p= like this example :

Method Shown

public static string cleanString(string input)
{
    if (input.Contains("p=") && input.Contains("&"))
    {
        int startPos = input.IndexOf("p=");
        int endPos = input.IndexOf("&",startPos);
        input = input.Substring(0,startPos) + 
                                       input.Substring(endPos+1,(input.Length-1)-endPos);
    }

    return input;
}

Usage

cleanString("abc-def-c?p=2&x=5&z=6"));
cleanString("abc-def-c?"));

Replacing characters between two characters

3 Answers3