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?

Answer 1

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);

Answer 2

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);

Answer 3

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.)

Answer 4

Uri 类通常是操作 Urls 的最佳选择。

Answer 5

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.

Answer 6

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

Answer 7

you can use .NET's built in method to remove the QueryString . ie, 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.

Answer 8

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.

Answer 9

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;
    }