CODEWITHSUNDEEP
c#regex
ONYX
ONYX

Reputation: 5859

How do get the first occurrence of a char in Substring

I'm trying to get the first occurrence in my substring start point:

string dir = Request.MapPath(Request.ApplicationPath) + "\\App_GlobalResources\\";

foreach (var file in Directory.EnumerateFiles(dir, "*.resx"))
{
    ddlResources.Items.Add(new ListItem { Text = file.Substring(firstoccuranceof("."), file.LastIndexOf(".")), Value = file });
}

if I do file.Substring(file.IndexOf("."), file.LastIndexOf(".")) I get an error

Upvotes: 20

Views: 73432

Answers (7)

MikeRyz
MikeRyz

Reputation: 289

Here you go!)

Using a string variable type

int index = str.IndexOf(@"\");

"C:\Users\somebody\Desktop\aFolder\someFile"

https://www.peachpit.com/articles/article.aspx?p=31938&seqNum=12#:~:text=To%20find%20the%20first%20or,string%20you%20are%20searching%20for.

Upvotes: 0

John K
John K

Reputation: 28869

Because the original question is marked with the [regex] tag, I'll provide the following solution, however the best answer for simple parsing of paths using .NET is not by regex. 

//extracts "filename" from "filename.resx"
string name = Regex.Match("filename.resx", @"^(.*)\..+?$").Groups[1].Value;

Use an answer that relies on the Path class instead, for simplicity. Other answers contain that info.

Upvotes: 0

Ahmed Masud
Ahmed Masud

Reputation: 22372

I think that in your particular case you are NOT trying to get IndexOf... Instead you need to use 0 because you are trying to create a key based on filename if understand correctly:

`ddlResources.Items.Add(new ListItem(file.Substring(0, file.LastIndexOf(".")), file ));`

Also, you have '{}' in there as in new ListItem { ... } which is also going to cause a syntax error... Anyhow have a look..

Upvotes: 1

KV Prajapati
KV Prajapati

Reputation: 94645

Use IndexOf and LastIndexOf string methods to get index of first and last occurrence of "search" string. You may use System.IO.Path.GetExtension(), System.IO.Path.GetFileNameWithoutExtension(), and System.IO.Path.GetDirectoryName() methods to parse the path.

For instance,

string file = @"c:\csnet\info.sample.txt";
Console.WriteLine(System.IO.Path.GetDirectoryName(file));           //c:\csnet
Console.WriteLine(System.IO.Path.GetFileName(file));                //info.sample.txt
Console.WriteLine(System.IO.Path.GetFileNameWithoutExtension(file));//info.sample
Console.WriteLine(System.IO.Path.GetExtension(file));               //.txt

Upvotes: 8

James
James

Reputation: 591

file.IndexOf(".")

Should get you the first occurence of ".". Otherwise it will return -1 if not found.

Upvotes: 1

Reed Copsey
Reed Copsey

Reputation: 564433

To answer your actual question - you can use string.IndexOf to get the first occurrence of a character. Note that you'll need to subtract this value from your LastIndexOf call, since Substring's second parameter is the number of characters to fetch, not a start and end index.

However... Instead of parsing the names, you can just use Path.GetFilenameWithoutExtension to get the filename directly.

Upvotes: 23

Tomislav Markovski
Tomislav Markovski

Reputation: 12346

First occurence

String.IndexOf('.')

Last occurence

String.LastIndexOf('.')

Upvotes: 19

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