Remove file extension from a file name string

Question

If I have a string saying "abc.txt", is there a quick way to get a substring that is just "abc"?

I can't do an fileName.IndexOf('.') because the file name could be "abc.123.txt" or something and I obviously just want to get rid of the extension (i.e. "abc.123").

score 475 · Answer 1 · edited Feb 12 '13 at 00:17

475

The Path.GetFileNameWithoutExtension method gives you the filename you pass as an argument without the extension, as should be obvious from the name.

edited Feb 12 '13 at 00:17

ladenedge

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answered Sep 09 '11 at 01:22

R. Martinho Fernandes

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Was gonna suggest: string.Format( "{0}\\{1}", Path.GetDirectoryName( path ), Path.GetFileNameWithoutExtension( path ) ) ... but I saw an even better version below using Path.Combine instead of String.Format! – emery.noel Mar 16 '16 at 18:25
7

Preserving the path is not a desired effect, note that the method name is GetFileNameWithoutExtension. If path preservation was promised, then the method name should have been different. The method description is also quite specific, only the filename with no extension is returned. The OP doesn't specify that he requires the path. Quite the contrary. – Morten Bork Aug 22 '17 at 08:06
2

@dukevin nothing about this question has anything to do with the path. It simply asks for removal of extension from the *filename*. – Rory McCrossan Oct 16 '18 at 15:06
For those who need it, the fully qualified function name is System.IO.path.GetFileNameWithoutExtension – gouderadrian Sep 25 '20 at 08:33

Ran QUAN · Answer 2 · 2014-08-08T00:55:06.620

331

There's a method in the framework for this purpose, which will keep the full path except for the extension.

System.IO.Path.ChangeExtension(path, null);

If only file name is needed, use

System.IO.Path.GetFileNameWithoutExtension(path);

edited Aug 08 '14 at 00:55

answered Aug 06 '14 at 08:28

Ran QUAN

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This is the correct answer. The accepted answer strips file path – dukevin Oct 02 '15 at 22:01
9

This is a better answer as it preserves the path – James H Mar 11 '16 at 19:01
10

The `null` has a magic value here. If you use `String.Empty` aka `""` you will be left with a trailing [`.`] dot. – THBBFT Nov 09 '18 at 17:00
I disagree this answer is better. `GetFileNameWithoutExtension` is more explicit. Although it IS nice knowing about its potentially undesired side effect and the existence of an alternative to avoid it. – jeromej Jan 08 '20 at 13:23
1

Doesn't work in Powershell v5.1 or v7.1. The system interprets `[System.IO.Path]::ChangeExtension($FilePath,$null)` the same as `[System.IO.Path]::ChangeExtension($FilePath,'')` or `[System.IO.Path]::ChangeExtension($FilePath,[string]::Empty)`. – Bacon Bits Jun 22 '21 at 20:48

score 60 · Answer 3 · edited Sep 09 '11 at 01:40

60

You can use

string extension = System.IO.Path.GetExtension(filename);

And then remove the extension manually:

string result = filename.Substring(0, filename.Length - extension.Length);

edited Sep 09 '11 at 01:40

R. Martinho Fernandes

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answered Sep 09 '11 at 01:20

phdesign

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@Bio, actually that get's the length of the extension, and then grabs the filename up until the extension. – Neville Aug 01 '12 at 00:23
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If you decide to ignore System.IO.Path functionality is not better if you get the extension as: string extension = filename.Substring(filename.LastIndexOf('.')); ? – QMaster Sep 24 '18 at 17:13

score 33 · Answer 4 · answered Sep 09 '11 at 01:38

33

String.LastIndexOf would work.

string fileName= "abc.123.txt";
int fileExtPos = fileName.LastIndexOf(".");
if (fileExtPos >= 0 )
 fileName= fileName.Substring(0, fileExtPos);

answered Sep 09 '11 at 01:38

Andrew

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Watch out for files with no extension, like `foo/bar.cat/cheese`! – Cameron Jan 24 '14 at 14:54
`String.LastIndexOf` is dangerous for accomplishing something like this. For files with no extension, as @Cameron has stated above, your results may be not what you want. The safest way to do this is using [@Logman's answer above.](https://stackoverflow.com/a/19539419/325521) – Shiva Jul 03 '18 at 21:04
@Shiva but for logman answer you need access to the file. If you only have the filename as string.... – Leandro Bardelli Jun 16 '23 at 17:05

score 16 · Answer 5 · answered Oct 23 '13 at 10:40

16

If you want to create full path without extension you can do something like this:

Path.Combine( Path.GetDirectoryName(fullPath), Path.GetFileNameWithoutExtension(fullPath))

but I'm looking for simpler way to do that. Does anyone have any idea?

answered Oct 23 '13 at 10:40

Logman

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score 13 · Accepted Answer · edited Sep 05 '19 at 04:49

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I used the below, less code

string fileName = "C:\file.docx";
MessageBox.Show(Path.Combine(Path.GetDirectoryName(fileName),Path.GetFileNameWithoutExtension(fileName)));

Output will be

C:\file

edited Sep 05 '19 at 04:49

Marcel Gosselin

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answered Mar 05 '15 at 10:52

Benjym

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And what if my directory separator is '/' ;)? – Logman Dec 08 '16 at 17:11
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Use `Path.Combine()` rather than specifying `"\\"`. – Broots Waymb Dec 27 '16 at 16:33

score 4 · Answer 7 · answered Jun 30 '17 at 20:37

4

You maybe not asking the UWP api. But in UWP, file.DisplayName is the name without extensions. Hope useful for others.

answered Jun 30 '17 at 20:37

sudoer

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score 1 · Answer 8 · edited Mar 04 '14 at 10:59

1

if you want to use String operation then you can use the function lastIndexOf( ) which Searches for the last occurrence of a character or substring. Java has numerous string functions.

edited Mar 04 '14 at 10:59

Contango

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answered Sep 09 '11 at 01:25

Shraddha

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Emiliano Ruiz · Answer 9 · 2019-12-10T13:46:33.423

I know it's an old question and Path.GetFileNameWithoutExtensionis a better and maybe cleaner option. But personally I've added this two methods to my project and wanted to share them. This requires C# 8.0 due to it using ranges and indices.

public static string RemoveExtension(this string file) => ReplaceExtension(file, null);

public static string ReplaceExtension(this string file, string extension)
{
    var split = file.Split('.');

    if (string.IsNullOrEmpty(extension))
        return string.Join(".", split[..^1]);

    split[^1] = extension;

    return string.Join(".", split);
}

score -1 · Answer 10 · answered Nov 12 '22 at 05:07

ReadOnlySpan<char> filename = "abc.def.ghi.txt";
var fileNameWithoutExtension = RemoveFileExtension(filename); //abc.def.ghi

string RemoveFileExtension(ReadOnlySpan<char> path)
{
    var lastPeriod = path.LastIndexOf('.');
    return (lastPeriod < 0 ? path : path[..lastPeriod]).ToString();
}

score -3 · Answer 11 · answered Oct 18 '13 at 04:14

-3

    /// <summary>
    /// Get the extension from the given filename
    /// </summary>
    /// <param name="fileName">the given filename ie:abc.123.txt</param>
    /// <returns>the extension ie:txt</returns>
    public static string GetFileExtension(this string fileName)
    {
        string ext = string.Empty;
        int fileExtPos = fileName.LastIndexOf(".", StringComparison.Ordinal);
        if (fileExtPos >= 0)
            ext = fileName.Substring(fileExtPos, fileName.Length - fileExtPos);

        return ext;
    }

answered Oct 18 '13 at 04:14

shmaltzy

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This doesn't answer the question. – Rapptz Jun 16 '14 at 13:29
1

Why would you write an extension method for this? Aside from this very specific case, String.GetFileExtension() makes no sense whatsoever. However, the function is carried over everywhere, and it's supposed to denote behavior specific to any String. Which is not the case. – Jun 16 '14 at 13:33

score -6 · Answer 12 · edited May 11 '15 at 08:12

        private void btnfilebrowse_Click(object sender, EventArgs e)
        {
            OpenFileDialog dlg = new OpenFileDialog();
            //dlg.ShowDialog();
            dlg.Filter = "CSV files (*.csv)|*.csv|XML files (*.xml)|*.xml";
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                string fileName;
                fileName = dlg.FileName;
                string filecopy;
                filecopy = dlg.FileName;
                filecopy = Path.GetFileName(filecopy);
                string strFilename;
                strFilename = filecopy;
                 strFilename = strFilename.Substring(0, strFilename.LastIndexOf('.'));
                //fileName = Path.GetFileName(fileName);             

                txtfilepath.Text = strFilename;

                string filedest = System.IO.Path.GetFullPath(".\\Excels_Read\\'"+txtfilepath.Text+"'.csv");
               // filedest = "C:\\Users\\adm\\Documents\\Visual Studio 2010\\Projects\\ConvertFile\\ConvertFile\\Excels_Read";
                FileInfo file = new FileInfo(fileName);
                file.CopyTo(filedest);
             // File.Copy(fileName, filedest,true);
                MessageBox.Show("Import Done!!!");
            }
        }

Please don't just post code, it's a lot more helpful to explain your answer alongside the code. — SuperBiasedMan, May 11 '15 at 07:52
Large part of the code is completely irrelevant. Explanation is missing. This is not useful. — Palec, Jan 12 '16 at 10:14
The code is too specific to a problem different from one in question. — Dominic Bett, May 19 '17 at 14:47

score -6 · Answer 13 · answered Jul 07 '15 at 16:44

-6

This implementation should work.

string file = "abc.txt";
string fileNoExtension = file.Replace(".txt", "");

answered Jul 07 '15 at 16:44

Dominic Bett

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What about `abc.txt.pdf`? :-) – Palec Jan 12 '16 at 10:13

Remove file extension from a file name string

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