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How to split a defined string from another string and get the first item after split

I have this string D:\ASN\Documents\ENU\LO\ANL\File\05003ede-59bf-45c6-bb57-a6111e9f18e0\linux-cheat-sheet.pdf and I want to exclude this string D:\ASN\Documents\ENU\LO from the above string and then get the first string(in this case ANL)after the split.
I tried something like this:
string fullpath = "D:\\ASN\\Documents\\ENU\\LO\\ANL\\File\\05003ede-59bf-45c6-bb57-a6111e9f18e0\\linux-cheat-sheet.pdf"
string[] sep = new string[]{"D:\\ASN\\Documents\\ENU\\LO"};
string [] result = fullpath.split(stringSeparators, StringSplitOptions.RemoveEmptyEntries);
foreach (string s in result)
{
Console.Write(s.Substring(s.IndexOf(#"\") + 1));
}
But this is giving me ANL\File\05003ede-59bf-45c6-bb57-a6111e9f18e0\linux-cheat-sheet.pdf". Instead I need only ANL. How can this be achieved? Is there any other way to get this instead of this way.
TIA

var result = fullpath.Replace(samplePath, "").Split('\\')[1];
You can replace the first part (samplePath) with nothing, removing it (or you could use Substring to get the second part of the fullPath, counting the characters of samplePath), and then Split the result on '\', getting the second occurrence, which is the result you expect.
Here's a working version: https://dotnetfiddle.net/k4tfGP

Can you do a split on the second string when it sees the \?
String sampleString = "ANL\File\05003ede-59bf-45c6-bb57-a6111e9f18e0\linux-cheat-sheet.pdf"";
String[] stringArray = sampleString.split("\");
String wantedString = stringArray[0];

This is not what split() is intended for. split() is generally used to divide your string into multiple sections based on a separator. In your case, you might have wanted to use it to separate the sub-folders by splitting on '\'.
But you want something else -- to remove a section of text. If you know that the text will always be at the start, try this:
string result = fullpath.Substring("D:\\ASN\\Documents\\ENU\\LO".Length);
This will return the original string, minus the first X characters, where X is exactly the length of the string you want to remove.

string fullpath =
"D:\\ASN\\Documents\\ENU\\LO\\ANL\\File\\05003ede-59bf-45c6-bb57-a6111e9f18e0\\linux-cheat-sheet.pdf";
string[] sep = new string[] {"D:\\ASN\\Documents\\ENU\\LO"};
string[] result = fullpath.Split(sep, StringSplitOptions.RemoveEmptyEntries);
foreach (string s in result)
{
Console.Write(s.Substring(s.IndexOf(#"\") + 1, s.IndexOf(#"\", 2) - 1));
}
String.IndexOf will get you the index of the first, but has overloads giving a starting point. So In this example, I have given the starting point as "2" as your path contains "\\" always.

string basepath = "D:\\ASN\\Documents\\ENU\\LO\\";
string fullpath = "D:\\ASN\\Documents\\ENU\\LO\\ANL\\File\\05003ede-59bf-45c6-bb57-a6111e9f18e0\\linux-cheat-sheet.pdf";
fullpath = fullpath.Replace(basepath, "");
string returnValue = fullpath.Remove(fullpath.IndexOf("\\"), fullpath.Length-fullpath.IndexOf("\\"));
Worked here...

Split a string at 2 points

I have a file called file_test1.txt and I want to extract just test1 from the name and place it in a string. Whats the best way of doing this?
E.g.
string fullfile = #"C:\file_test1.txt";
string section = [test1] from fullfile; // <- expected result
I want to be able to split on 'file_' and '.txt' as the 'test1' section could be larger or smaller however the 'file_' and '.txt' will always be the same.

Try Path.GetFileNameWithoutExtension(fullfile).Substring(5) (or Substring("TEMPLATE_PREFIX".Length))

You can try spilt
var test = Path.GetFileNameWithoutExtension(fullfile).split('_')[1];

Try following
string fullfile = #"C:\file_test1.txt";
var name = fullfile.Substring(8,fullfile.Length-12)
As c:\file_ and .txt are fixed, You can take Substring starting at index 8 (skip leading name), upto length of total string length - 12 (12 => length of leading name, and trailing extension)

Thought I'd give a solution that uses Split and handles files with multiple underscores:
string.Join("_", Path.GetFileNameWithoutExtension(file).Split('_').Skip(1));

String.Split() works quite well for my uses:
http://msdn.microsoft.com/en-us/library/b873y76a.aspx

Obviously many ways to accomplish this. Here's yet another approach:
string fullfile = #"C:\file_test1.txt";
int index1 = fullfile.LastIndexOf("file_");
if (index1 != -1)
{
int index2 = fullfile.IndexOf(".", index1);
if (index2 != -1)
{
string section = fullfile.Substring(index1 + 5, index2 - index1 - 5);
}
}

You could also get "test1", or any subsequent filename (assuming your file naming convention remains constant!) using this regular expression:
var defaultRegex = new Regex(#"(?<=_).*(?=.txt)");
var matches = defaultRegex.Matches(fullfile);
var match = matches[0].Value;
The regular expression:
(?<=_).*(?=.txt)
uses positive look behind to find text preceded by '_', and also positive lookahead to find text which has '.txt' ahead of it.

How to extract string at a certain character that is repeated within string?

How can I get "MyLibrary.Resources.Images.Properties" and "Condo.gif" from a "MyLibrary.Resources.Images.Properties.Condo.gif" string.
I also need it to be able to handle something like "MyLibrary.Resources.Images.Properties.legend.House.gif" and return "House.gif" and "MyLibrary.Resources.Images.Properties.legend".
IndexOf LastIndexOf wouldn't work because I need the second to last '.' character.
Thanks in advance!
UPDATE
Thanks for the answers so far but I really need it to be able to handle different namespaces. So really what I'm asking is how to I split on the second to last character in a string?

You can use LINQ to do something like this:
string target = "MyLibrary.Resources.Images.Properties.legend.House.gif";
var elements = target.Split('.');
const int NumberOfFileNameElements = 2;
string fileName = string.Join(
".",
elements.Skip(elements.Length - NumberOfFileNameElements));
string path = string.Join(
".",
elements.Take(elements.Length - NumberOfFileNameElements));
This assumes that the file name part only contains a single . character, so to get it you skip the number of remaining elements.

You can either use a Regex or String.Split with '.' as the separator and return the second-to-last + '.' + last pieces.

You can look for IndexOf("MyLibrary.Resources.Images.Properties."), add that to MyLibrary.Resources.Images.Properties.".Length and then .Substring(..) from that position

If you know exactly what you're looking for, and it's trailing, you could use string.endswith. Something like
if("MyLibrary.Resources.Images.Properties.Condo.gif".EndsWith("Condo.gif"))
If that's not the case check out regular expressions. Then you could do something like
if(Regex.IsMatch("Condo.gif"))
Or a more generic way: split the string on '.' then grab the last two items in the array.

string input = "MyLibrary.Resources.Images.Properties.legend.House.gif";
//if string isn't already validated, make sure there are at least two
//periods here or you'll error out later on.
int index = input.LastIndexOf('.', input.LastIndexOf('.') - 1);
string first = input.Substring(0, index);
string second = input.Substring(index + 1);

Try splitting the string into an array, by separating it by each '.' character.
You will then have something like:
{"MyLibrary", "Resources", "Images", "Properties", "legend", "House", "gif"}
You can then take the last two elements.

Just break down and do it in a char loop:
int NthLastIndexOf(string str, char ch, int n)
{
if (n <= 0) throw new ArgumentException();
for (int idx = str.Length - 1; idx >= 0; --idx)
if (str[idx] == ch && --n == 0)
return idx;
return -1;
}
This is less expensive than trying to coax it using string splitting methods and isn't a whole lot of code.
string s = "1.2.3.4.5";
int idx = NthLastIndexOf(s, '.', 3);
string a = s.Substring(0, idx); // "1.2"
string b = s.Substring(idx + 1); // "3.4.5"

how to place - in a string

I have a string "8329874566".
I want to place - in the string like this "832-98-4566"
Which string function can I use?

I would have done something like this..
string value = "8329874566";
value = value.Insert(6, "-").Insert(3, "-");

You convert it to a number and then format the string.
What I like most about this is it's easier to read/understand what's going on then using a few substring methods.
string str = "832984566";
string val = long.Parse(str).ToString("###-##-####");

There may be a tricky-almost-unreadable regex solution, but this one is pretty readable, and easy.
The first parameter of the .Substring() method is where you start getting the characters, and the second is the number of characters you want to get, and not giving it sets a default as value.length -1 (get chars until the end of the string):
String value = "8329874566";
String Result = value.Substring(0,3) + "-" + value.Substring(3,2) + "-" + value.Substring(6);
--[edit]--
Just noticed you didn't use one of the numbers AT ALL (number '7') in the expected result example you gave, but if you want it, just change the last substring as "5", and if you want the '7' but don't want 5 numbers in the last set, let it like "5,4".

Are you trying to do this like American Social Security numbers? I.e., with a hyphen after the third and and fifth numerals? If so:
string s = "8329874566";
string t = String.Format("{0}-{1}-{2}", s.Substring(0, 3), s.Substring(3, 2), s.Substring(5));

Just out of completeness, a regular expression variant:
Regex.Replace(s, #"(\d{3})(\d{2})(\d{4})", "$1-$2-$3");
I consider the Insert variant to be the cleanest, though.

This works fine, and I think that is more clear:
String value = "8329874566";
value = value.Insert(3, "-").Insert(6, "-");
The console outputs shows this:
832-98-74566

If the hyphens are to go in the same place each time, then you could simply concatenate together the pieces of the orginal string like this:
// 0123456789 <- index
string number = "8329874566";
string new = number.Substring(0, 3) + "-" + number.Substring(3, 2) + "-" + number.Substring(5);
For a general way of making mutable strings, use the StringBuilder class. This allows deletions and insertions to be made before calling ToString to produce the final string.

You could try the following:
string strNumber = "8329874566"
string strNewNumber = strNumber.Substring(0,3) + "-" + strNumber.Substring(4,2) + "-" strNumber.Substring(6)
or something in this manner

string val = "832984566";
string result = String.Format("{0}-{1}-{2}", val.Substring(0,3), val.Substring(3,2), val.Substring(5,4));

var result = string.Concat(value.Substring(0,3), "-", value.Substring(3,2), "-", value.Substring(5,4));
or
var value = "8329874566".Insert(3, "-").Insert(6, "-");

Now how about this for a general solution?
// uglified code to fit within horizontal limits
public static string InsertAtIndices
(this string original, string insertion, params int[] insertionPoints) {
var mutable = new StringBuilder(original);
var validInsertionPoints = insertionPoints
.Distinct()
.Where(i => i >= 0 && i < original.Length)
.OrderByDescending(i => i);
foreach (int insertionPoint in validInsertionPoints)
mutable.Insert(insertionPoint, insertion);
return mutable.ToString();
}
Usage:
string ssn = "832984566".InsertAtIndices("-", 3, 5);
string crazy = "42387542342309856340924803"
.InsertAtIndices(":", 1, 2, 3, 4, 5, 6, 17, 200, -1, -1, 2, 3, 3, 4);
Console.WriteLine(ssn);
Console.WriteLine(crazy);
Output:
832-98-4566
4:2:3:8:7:5:42342309856:340924803
Overkill? Yeah, maybe...
P.S. Yes, I am regex illiterate--something I hope to rectify someday.

A straightforward (but not flexible) approach would be looping over the characters of the string while keeping a counter running. You can then construct a new string character by character. You can add the '-' character after the 3rd and 5th character.
A better approach may be to use a function to insert a single character in the middle of the string at a specific index. String.Insert() would do well. The only thing to pay attention to here is that the string indexes will get off by one with each insert.
EDIT more language-specific as per comments

C# Using Substring, how do I extract this string?

I want to extract the first folder in the URL below, in this example it is called 'extractThisFolderName' but the folder could have any name and be any length. With this in mind how can I use substring to extract the first folder name?
The string: www.somewebsite.com/extractThisFolderName/leave/this/behind
String folderName = path.Substring(path.IndexOf(#"/"),XXXXXXXXXXX);
It's the length I'm struggling with.

If you're getting a Uri, why not just do uri.Segments[0]?
Or even path.Split(new Char[] { '/' })[1] ?

If you're going to be using each path part, you can use:
String[] parts = path.Split('/');
At which point you can access the "extractThisFolderName" part by accessing parts[1].
Alternatively, you can do this to splice out the foldername:
int firstSlashIndex = path.IndexOf('/');
int secondSlashIndex = path.IndexOf('/', firstSlashIndex + 1);
String folderName = path.Substring(firstSlashIndex + 1, secondSlashIndex - firstSlashIndex);

Daniel's answer gives you other practical ways of doing it. Another alternative using substring:
int start = path.IndexOf('/')+1; // Note that you don't need a verbatim string literal
int secondSlash = path.IndexOf('/', start);
return path.Substring(start, secondSlash-start);
You'll want to add some error checking in there, of course :)

The problem also lends itself to regular expressions. An expression like:
(?<host>.*?)/(?<folder>.*?)/
Is clear about what's going on and you can get the data out by those names.

int start = path.IndexOf('/');
int end = path.IndexOf('/', start + 1);
if (end == -1) end = path.Length;
string folderName = path.Substring(start + 1, end - start - 1);
EDIT: Daniel Schaffer's answer about using uri segments is preferable, but left this in as it may be your path is not really a valid uri.

You could do:
string myStr = "www.somewebsite.com/extractThisFolderName/leave/this/behind";
int startIndex = myStr.IndexOf('/') + 1;
int length = myStr.IndexOf('/', startIndex) - startIndex;
Console.WriteLine(myStr.Substring(startIndex, length));
At the same point I assume this is being done in ASP.Net if so I think there might be another way to get this without doign the querying.

folderName.Split('/')[1]