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

问题:

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?

回答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); 

回答2:

To remove everything before first "/"

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

To remove everything after first "/"

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

To remove everything before last "/"

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

To remove everything after last "/"

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

Even more simpler option for removing characters after specified char is to use string.Remove() method as follows:

To remove everything after first "/"

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

To remove everything after last "/"

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

回答3:

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

回答4:

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

回答5:

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.

回答6:

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.

回答7:

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.

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