How to replace a specific character in url with a "" only after the?

Question

I want to replace the & from the url which come after ? i.e query string.

Example
http://stackoverflow.com&amp;/questions/ask?a=abcd&amp;b=bcd&amp;-------->1

Suppose there is a Url as 1 Now I want to replace the amp; with ""

http://stackoverflow.com&amp;/questions/ask?a=abcd&b=bcd&-------->2

I have tried this regex as

\?(.*?&(amp;).*?){1,} for using Regex.Replace(......);

I want to replace group[2] with "". How to do that??????????

I believe you need a [lookaround](http://www.regular-expressions.info/lookaround.html). — AgentFire, Dec 10 '13 at 07:56
`&` is HTML Name of `&` I thought you should see what thomas suggest — Sabilv, Dec 10 '13 at 08:08

Casimir et Hippolyte · Accepted Answer · 2013-12-10T08:15:41.363

0

You can use this:

string pattern = @"((?:\?|\G(?<!^))(?:[^&]+|&(?!amp;))*&)amp;";
string replacement = "$1";
Regex rgx = new Regex(pattern);
string result = rgx.Replace(input, replacement);

Pattern details:

(                         # capturing group: content after ? and before &amp; 
    (?:                   # non capturing group: entry point
        \?                # literal ?
      |                   # OR
        \G(?<!^)          # a match contiguous to a precedent match
    )
    (?:[^&]+|&(?!amp;))*  # all that is not a & or a & not followed by "amp;"
&                         # literal & before "amp;"
)
amp;

edited Dec 10 '13 at 08:15

answered Dec 10 '13 at 07:59

Casimir et Hippolyte

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@user3085864: The edited version works (tested), don't forget to change the replacement pattern too. – Casimir et Hippolyte Dec 10 '13 at 13:21

score 0 · Answer 2 · edited May 23 '17 at 12:29

0

You probably don't want to replace amp; by nothing, but & by &.

I suppose Regex is not the correct thing to use here. See Get url parameters from a string in .NET on how to extract parameters from a URL. This will automatically convert & to &

edited May 23 '17 at 12:29

Community

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answered Dec 10 '13 at 08:00

Thomas Weller

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How to replace a specific character in url with a "" only after the?

2 Answers2