CODEWITHSUNDEEP
c#string
user2487873
user2487873

Reputation:

C# string trimming

I am having trouble on how i should trim this string. I want everything after the last '/' to be deleted, but there are multiple '/'.

Example:

From:http://stackoverflow.com/questions/ask/randomcrap.html

To: http://stackoverflow.com/questions/ask/

Upvotes: 0

Views: 936

Answers (9)

Nico
Nico

Reputation: 12683

String trimming can be done using many of the built in string utlitites.

First you want the LastIndexOf the "/" character in the string, and then you want use the Substring method from the index of 0 (start of the string) to the index of the / character. Now this will return everything to the last / if you want to include the slash you have to add one more index.

        static string getToLastSlash(string inString)
        {
            var index = inString.LastIndexOf('/');
            if (index == -1)
                throw new Exception("/ not found in string");

            return inString.Substring(0, index + 1);
        }

The LastIndexOf() method will return the last index of a specific character or string provided. If the LastIndexOf() method does not evaluate a match the result will be -1. Given the fact that you could have a non-match, you must first check if the match result is -1. In the above method we simply throw an exception however your application may have an alternative method to handle this situation.

If the match is greater that -1 then you can assume a match was found. When a match was found you can use the Substring() method to parse all the characters in the string starting at position 0 to the index+1.

Upvotes: 10

Dmitrii Bychenko
Dmitrii Bychenko

Reputation: 186688

If you want to find out the last '/' character, just use String LastIndexOf method:

  String text = @"http://stackoverflow.com/questions/ask/randomcrap.html";
  String result = text;

  int index = text.LastIndexOf('/'); // <- last '/' if any

  if (index >= 0) // <- if there's '/' within the string, trim it 
    result = text.Substring(0, index + 1);

  ...

  Console.Out.Write(result); // <- http://stackoverflow.com/questions/ask/

Upvotes: 0

Damith
Damith

Reputation: 63065

I think you can do this by using Uri class 

Uri parent = new Uri(uri, ".");

Upvotes: 2

Aaron Anodide
Aaron Anodide

Reputation: 17186

void Main()
{   
    Console.WriteLine (TrimLastPart("http://stackoverflow.com/questions/ask/randomcrap.html"));
    Console.WriteLine (TrimLastPart("http://stackoverflow.com/questions/ask//randomcrap.html"));
}

enum State
{
    SlashNotEncountered,
    SlashEncountered,
    BuildingResult
}

string TrimLastPart(string input)
{
    string result = string.Empty;
    State state = State.SlashNotEncountered;    
    foreach (var c in input.ToCharArray().Reverse())
    {
        switch (state)
        {
            case State.SlashNotEncountered:
                if(c == '/')
                {
                    state = State.SlashEncountered;
                }
                break;  
            case State.SlashEncountered:
                if(c != '/')
                {
                    state = State.BuildingResult;
                    result = c.ToString();
                }
                break;  
            case State.BuildingResult:
                result = c + result;
                break;
        }
    }
    return result + "/";
}

Output:

http://stackoverflow.com/questions/ask/
http://stackoverflow.com/questions/ask/

Upvotes: 0

NucS
NucS

Reputation: 629

You can Split the char '/' then convert it to a List<string> and remove the last item and finally reunite the parts using string.Join

var url = "http://stackoverflow.com/questions/ask/randomcrap.html";
var b = url.Replace("http://", "").Split('/').ToList(); //replace "html://" to avoid problems with the split
b.RemoveAt(b.Count-1); //last index

var result = "http://" + string.Join("/", b) + "/";

result equals to "http://stackoverflow.com/questions/ask/"

This will allow you to remove any part you wish.
Don't forget you could also use b.RemoveRange(int index, int count);

Upvotes: 0

Daniel B
Daniel B

Reputation: 8879

Most simple way would probably be

string myURL = "http://stackoverflow.com/questions/ask/randomcrap.html";
string str = myURL.Substring(0, myURL.LastIndexOf('/'));
Console.WriteLine(str);

which will output

http://stackoverflow.com/questions/ask

Upvotes: 1

user2246674
user2246674

Reputation: 7719

I would use a regular expression Replace with an end ($) anchor.

var res = Regex.Replace(input,
    @"[^/]+$", // match all the non-slashes anchored to the end of input
    "");       // replace any matched characters with nothing

// and make sure to use "res"

I prefer to use a regular expression for tasks like this - because I find it simpler and it can avoid an extra conditional guard "for free" - but make sure to understand the mechanics of the approach used.

Upvotes: 3

keyboardP
keyboardP

Reputation: 69372

You can use LastIndexOf like this

string str = "http://stackoverflow.com/questions/ask/randomcrap.html";
string final = RemoveAfterLastChar(str, '/');

public string RemoveAfterLastChar(string input, char c)
{
    var index = input.LastIndexOf(c);

    if (index != -1)
        return input.Substring(0, index + 1);
    else
        return input;
}

Or, if the format is always going to be the same as your example, you could use Path.GetDirectoryName.

input = Path.GetDirectoryName(input);

Upvotes: 0

Guvante
Guvante

Reputation: 19203

Combining string.Substring and string.LastIndexOf should do the trick.

Upvotes: 2

Related Questions