Remove characters after specific character in string, then remove substring?

Question

I feel kind of dumb posting this when this seems kind of simple and there are tons of questions on strings/characters/regex, but I couldn't find quite what I needed (except in another language: Remove All Text After Certain Point).

I've got the following code:

[Test]
    public void stringManipulation()
    {
        String filename = "testpage.aspx";
        String currentFullUrl = "http://localhost:2000/somefolder/myrep/test.aspx?q=qvalue";
        String fullUrlWithoutQueryString = currentFullUrl.Replace("?.*", "");
        String urlWithoutPageName = fullUrlWithoutQueryString.Remove(fullUrlWithoutQueryString.Length - filename.Length);

        String expected = "http://localhost:2000/somefolder/myrep/";
        String actual = urlWithoutPageName;
        Assert.AreEqual(expected, actual);
    }

I tried the solution in the question above (hoping the syntax would be the same!) but nope. I want to first remove the queryString which could be any variable length, then remove the page name, which again could be any length.

How can I get the remove the query string from the full URL such that this test passes?

Elliot Cameron · Accepted Answer · 2021-06-08 18:06:43Z

340

For string manipulation, if you just want to kill everything after the ?, you can do this

string input = "http://www.somesite.com/somepage.aspx?whatever";
int index = input.IndexOf("?");
if (index >= 0)
   input = input.Substring(0, index);

Edit: If everything after the last slash, do something like

string input = "http://www.somesite.com/somepage.aspx?whatever";
int index = input.LastIndexOf("/");
if (index >= 0)
    input = input.Substring(0, index); // or index + 1 to keep slash

Alternately, since you're working with a URL, you can do something with it like this code

System.Uri uri = new Uri("http://www.somesite.com/what/test.aspx?hello=1");
string fixedUri = uri.AbsoluteUri.Replace(uri.Query, string.Empty);

edited Jun 8, 2021 at 18:06

Elliot Cameron

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answered Apr 18, 2010 at 1:19

Anthony Pegram

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6 Comments

Charlie Salts Over a year ago

Or would it be the last / ?

Anthony Pegram Over a year ago

Oh, yeah, re-read that. He can do LastIndexOf("/") in that case.

gsvirdi Over a year ago

Lets says that my input string is always like http://www.somesite.com/somepage.aspx and I just want to fetch the last value (somepage.aspx or abc.xml) from it. Then what to do... ???

Anthony Pegram Over a year ago

@gsvirdi, in that case, you may load that URL into Uri uri, and then access uri.Segments. That will return an array, and "somepage.aspx" will be the last item.

ePandit Over a year ago

Its shorter single line equivalent is: input = input.Substring(0, input.LastIndexOf("/")+1);

|

Krisztián Balla · Accepted Answer · 2019-01-09 07:32:26Z

152

To remove everything before the first /

input = input.Substring(input.IndexOf("/"));

To remove everything after the first /

input = input.Substring(0, input.IndexOf("/") + 1);

To remove everything before the last /

input = input.Substring(input.LastIndexOf("/"));

To remove everything after the last /

input = input.Substring(0, input.LastIndexOf("/") + 1);

An even more simpler solution for removing characters after a specified char is to use the String.Remove() method as follows:

To remove everything after the first /

input = input.Remove(input.IndexOf("/") + 1);

To remove everything after the last /

input = input.Remove(input.LastIndexOf("/") + 1);

edited Jan 9, 2019 at 7:32

Krisztián Balla

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answered Sep 22, 2014 at 0:12

ePandit

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1 Comment

Elezar Over a year ago

Be aware that these will all throw an exception if the string doesn't contain a "/" at all. Obviously this won't be an issue if you're working with hard-coded strings as in the original question, but in most cases, you'll want to take that into consideration.

Joy Pinckard · Accepted Answer · 2019-01-26 15:30:20Z

18

Here's another simple solution. The following code will return everything before the '|' character:

if (path.Contains('|'))
   path = path.Split('|')[0];

In fact, you could have as many separators as you want, but assuming you only have one separation character, here is how you would get everything after the '|':

if (path.Contains('|'))
   path = path.Split('|')[1];

(All I changed in the second piece of code was the index of the array.)

answered Jan 26, 2019 at 15:30

Joy Pinckard

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Comments

Ian Mercer · Accepted Answer · 2021-04-30 01:44:53Z

4

The Uri class is generally your best bet for manipulating Urls.

edited Apr 30, 2021 at 1:44

answered Apr 18, 2010 at 1:26

Ian Mercer

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1 Comment

Trevor Over a year ago

An example of link would be nice.

Fyodor Soikin · Accepted Answer · 2010-04-18 11:29:44Z

1

I second Hightechrider: there is a specialized Url class already built for you.

I must also point out, however, that the PHP's replaceAll uses regular expressions for search pattern, which you can do in .NET as well - look at the RegEx class.

answered Apr 18, 2010 at 11:29

Fyodor Soikin

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Comments

TGarrett · Accepted Answer · 2014-09-16 11:52:00Z

1

To remove everything before a specific char, use below.

string1 = string1.Substring(string1.IndexOf('$') + 1);

What this does is, takes everything before the $ char and removes it. Now if you want to remove the items after a character, just change the +1 to a -1 and you are set!

But for a URL, I would use the built in .NET class to take of that.

answered Sep 16, 2014 at 11:52

TGarrett

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Comments

M. Adeel Khalid · Accepted Answer · 2017-03-20 07:41:55Z

1

Request.QueryString helps you to get the parameters and values included within the URL

example

string http = "http://dave.com/customers.aspx?customername=dave"
string customername = Request.QueryString["customername"].ToString();

so the customername variable should be equal to dave

regards

edited Mar 20, 2017 at 7:41

M. Adeel Khalid

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answered Dec 15, 2014 at 22:13

dave

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Comments

Chad Carisch · Accepted Answer · 2014-09-20 23:26:38Z

0

you can use .NET's built in method to remove the QueryString. i.e., Request.QueryString.Remove["whatever"];

here whatever in the [ ] is name of the querystring which you want to remove.

Try this... I hope this will help.

edited Sep 20, 2014 at 23:26

Chad Carisch

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answered Apr 9, 2014 at 12:54

shary.sharath

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Comments

Kye · Accepted Answer · 2022-12-29 08:46:58Z

0

You can use this extension method to remove query parameters (everything after the ?) in a string

public static string RemoveQueryParameters(this string str)
    {
        int index = str.IndexOf("?");
        return index >= 0 ? str.Substring(0, index) : str;
    }

answered Dec 29, 2022 at 8:46

Kye

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Comments

ToolmakerSteve · Accepted Answer · 2024-07-17 21:52:03Z

Here is a method that provides some options re what to keep.

        /// <summary> Keep start of string until find "match".
        /// If "match" not found, keep entire string.
        /// If "includeMatch", "match" is kept in result, otherwise is excluded.
        /// If "lastMatch", and there are multiple "matches", the LAST one is used as the match.
        /// </summary>
        static public string KeepUntil(string s, string match, bool includeMatch = false, bool lastMatch = false)
        {
            if (string.IsNullOrEmpty(s) || string.IsNullOrEmpty(match))
                return s;

            int index = (lastMatch ? s.LastIndexOf(match) : s.IndexOf(match));
            if (index < 0)
                return s;

            if (includeMatch)
                index += match.Length;
            return s.Substring(0, index);
        }

Usage:

To remove everything after last "/":

var currentFullUrl = "http://localhost:2000/somefolder/myrep/test.aspx?q=qvalue";
var result = KeepUntil(currentFullUrl, "/", includeMatch: true, lastMatch: true);
var expected = "http://localhost:2000/somefolder/myrep/";

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