Develop Reference

How to extract preceding strings in a given directory

The folder names are variable but I have this constant value in the directory - the "distributions" folder.
How can I extract the all the strings before the "distributions" folder?
> /<root>/win/<usr>/distributions/<dbms>/<repository>/<port
> type>/<remote system>/<port>
Currently I'm doing it in lengthy way (e.g. getting the length of the whole directory, finding the location of distributions word in the string, etc...).
I'm looking for a more elegant way. Could this be done using Regex, or a shorter version of my current implementation?

string.Split followed by TakeWhile can help you
var resultArray = str.Split(new []{#"/"},StringSplitOptions.RemoveEmptyEntries)
.TakeWhile(x=>!x.Equals("distributions"));
Output
<root>
win
<usr>
Update based on Commments
If you need entire path based before "distributions", You can use
var result = str.Split(new []{#"distributions"},StringSplitOptions.RemoveEmptyEntries)
.First();
Output
/<root>/win/<usr>/

string.split('/') will put each "component" of the path (or any string) in an array splitting them by delimiter (/ here). you could then loop through it.

Assuming you do want to get the path up until that point i would recommend using regex here is how i would do it.
Regex regex = new Regex(#".+?(?=distributions)");
Debug.WriteLine(regex.Match("/<root>/win/<usr>/distributions/<dbms>/<repository>").Value);
this outputs
/<root>/win/<usr>/

What is the problem with the good old way?
var s = "/<root>/win/<usr>/distributions/<dbms>/<repository>/<port.....";
var result = s.Substring(0, s.IndexOf("distributions"));
or s.Substring(0, s.IndexOf("/distributions/")+1) if that text might appeare in other form too...

How to read text file between ""

I need an "idea" on how to read text file data between quotes. For example:
line 1: "read a title"
line 2: "read a descr"
line 1: "read a title"
line 2: "read a descr"
I want to do a foreach type of thing, and I want to read all Line 1's, and Line 2's as a pair, but between the ".
In my program I am going to output (foreach of course):
readTerminatedNull(file1);
readTerminatedNull(file2);
I would read line by line, but some of the text could be:
line 1: "read a super long
title that goes off"
line 2: "read a descr"
So that's why I want to read between the ".
Sorry if that is too complicated, and it's a little hard to explain.
Edit:
Thanks for all the feed back guys, but I'm not sure you are getting what I am trying to do :p not your faults, I wrote this kinda wierd.
I will have a text file full of refrences, and text. like so.
text inside:
Refren: "myrefrence_1"
String: "This is a string of a refrence"
Refren: "myrefrence_2"
String: "hello world"
Refren: "myrefrence_3"
String: "I like cookies."
I want it to to read myrefrence_1 in the quotes of the first line, and then read the string in the next line between the ".
I will then stuff into my program that matches the refrence with the string.
But sometimes the text will be more than one line.
Refren: "this is text that goes and then
return keys on some parts."
and I still want it to read through the ".

(not tested, but you'll get the idea)
// Read all text from file
string sData = File.ReadAllText(#"c:/file.txt");
// Match strings between " "
Match match = Regex.Match(sData , "\"(\w|\d|\s|\\\")*\"",
RegexOptions.IgnoreCase);
// Read results and strip " out of them
foreach (var sResult in match) {
sResult = sResult.Remove(0,1).Remove(sResult.length-2, 1);
// Do whatever with sResult
}

You could learn some new tricks by looking into state machines. Basically: Read each character at a time and figure out what state you are in now. First, code this as a big while loop with a big switch statement inside. Then, go and read up on the state pattern for how to do this in an object oriented way. Then, ditch that and use delegates, because c# makes this stuff so easy to do.
Then, scrap it all, write some crappy Regular Expression with a multiline flag and slurp it the Perl way. Meditate on why this is the same as your original state machine solution.
Then, get really stuck in and learn about parser generators (lexx/yacc or some .NET variant) and write a simple BNF grammar for your problem. Take special note of how the trivial grammars used in the tutorials are all way more complicated than the one you need to write. Why is that so? Check out what Noam Chomsky had to say about that.
Eventually, you'll burn out. We all do. But you'll have so much fun digging into what makes programming the coolest activity on the planet. Burn-out is just the realization that that's a pipe dream ;)
When you're done, go outside. Meet people. Talk. Smile a lot. Be friendly. You're now a zen infused developer with a wicked grin. Yay for you! You rock!

What you're describing sounds like a single-column CSV file. The easiest way to access that is probably to use the Microsoft.VisualBasic.FileIO.TextFieldParser class, something like:
using (var csvParser = new TextFieldParser(new StringReader(content))
{
Delimiters = new[] {","},
HasFieldsEnclosedInQuotes = true
})
{
while (!csvParser.EndOfData)
{
var fields = csvParser.ReadFields();
Console.Print(fields[0]); //do something with the first (in your case only) field found.
}
}
Probably the easiest way to determine whether this approach makes sense, is to think about what happens if the string you're reading actually contains a double quote. Would it end up as "He said ""this is quoted"", but I wasn't listening" (doubling up the quotes), or is this situation impossible?
If the quotes would be doubled up in this way, then a standard CSV reader like this built-in framework one is probably your best bet.

To read all of the lines of the file you can use:
File.ReadAllLines(pathToFile);
to strip the text from "" you can use the substring method of string: http://msdn.microsoft.com/en-us/library/aka44szs.aspx
you can do it like that:
string strippedString = original.Substring(1, original.length -2);

Try this one
var text = File.ReadAllLines(pathToFile);
var lines = text.Split(':')
.Where((s,i) => i % 2 != 0)
.Select(s => s.trim('"'));

First of all you need to read in the file using:
File.ReadAllLines(filePath);
Then you could split all the lines using the string.Split function.
Splitting on the closing bracket would be your best bet.

As i have understood from you question is you want to read and write text file with some specific settings. is it ?
I would like to refer to to INI files which are the text files it self and provide the settings configurations as you wish to achieve. here are some links these could help you.
http://www.codeproject.com/Articles/1966/An-INI-file-handling-class-using-C
http://jachman.wordpress.com/2006/09/11/how-to-access-ini-files-in-c-net/

How to delete a string from a text file?

I currently have two strings assigned - domain,subdomain
How could I delete any matched occurrences of these strings in a text file?
string domain = "127.0.0.1 test.com"
string subdomain = "127.0.0.1 sub.test.com"
I don't think using a regex would be ideal in this situation.
How can this be done?

You need to:
Open the existing file for input
Open a new file for output
Repeatedly:
Read a line of text from the input
See if it matches your pattern (it's unclear at the moment what pattern you're looking for)
If it doesn't, write the line to the output (or if you're only trying to remove bits of lines, work out which bit you want to write out)
Close both the input and output (a using statement will do this automatically)
Optionally delete the original file and rename the new one if you want to effectively replace the original.

var result = Regex.Replace(File.ReadAllText("file.txt"),
#"127\.0\.0\.1 test\.com|127\.0\.0\.1 sub\.test\.com", string.Empty);
Then write to file obtained result.

Parsing a CSV File with C#, ignoring thousand separators

Working on a program that takes a CSV file and splits on each ",". The issue I have is there are thousand separators in some of the numbers. In the CSV file, the numbers render correctly. When viewed as a text document, they are shown like below:
Dog,Cat,100,100,Fish
In a CSV file, there are four cells, with the values "Dog", "Cat", "100,000", "Fish". When I split on the "," to an array of strings, it contains 5 elements, when what I want is 4. Anyone know a way to work around this?
Thanks

There are two common mistakes made when reading csv code: using a split() function and using regular expressions. Both approaches are wrong, in that they are prone to corner cases such as yours and slower than they could be.
Instead, use a dedicated parser such as Microsoft.VisualBasic.TextFieldParser, CodeProject's FastCSV or Linq2csv, or my own implemention here on Stack Overflow.

Typically, CSV files would wrap these elements in quotes, causing your line to be displayed as:
Dog,Cat,"100,100",Fish
This would parse correctly (if using a reasonable method, ie: the TextFieldParser class or a 3rd party library), and avoid this issue.
I would consider your file as an error case - and would try to correct the issue on the generation side.
That being said, if that is not possible, you will need to have more information about the data structure in the file to correct this. For example, in this case, you know you should have 4 elements - if you find five, you may need to merge back together the 3rd and 4th, since those two represent the only number within the line.
This is not possible in a general case, however - for example, take the following:
100,100,100
If that is 2 numbers, should it be 100100, 100, or should it be 100, 100100? There is no way to determine this without more information.

you might want to have a look at the free opensource project FileHelpers. If you MUST use your own code, here is a primer on the CSV "standard" format

well you could always split on ("\",\"") and then trim the first and last element.
But I would look into regular expressions that match elements with in "".

Don't just split on the , split on ", ".
Better still, use a CSV library from google or codeplex etc
Reading a CSV file in .NET?

You may be able to use Regex.Replace to get rid of specifically the third comma as per below before parsing?
Replaces up to a specified number of occurrences of a pattern specified in the Regex constructor with a replacement string, starting at a specified character position in the input string. A MatchEvaluator delegate is called at each match to evaluate the replacement.
[C#] public string Replace(string, MatchEvaluator, int, int);

I ran into a similar issue with fields with line feeds in. Im not convinced this is elegant, but... For mine I basically chopped mine into lines, then if the line didnt start with a text delimeter, I appended it to the line above.
You could try something like this : Step through each field, if the field has an end text delimeter, move to the next, if not, grab the next field, appaend it, rince and repeat till you do have an end delimeter (allows for 1,000,000,000 etc) ..
(Im caffeine deprived, and hungry, I did write some code but it was so ugly, I didnt even post it)

Do you know that it will always contain exactly four columns? If so, this quick-and-dirty LINQ code would work:
string[] elements = line.Split(',');
string element1 = elements.ElementAt(0);
string element2 = elements.ElementAt(1);
// Exclude the first two elements and the last element.
var element3parts = elements.Skip(2).Take(elements.Count() - 3);
int element3 = Convert.ToInt32(string.Join("",element3parts));
string element4 = elements.Last();
Not elegant, but it works.

Adding a Line to the Middle of a File with .NET

Hello I am working on something, and I need to be able to be able to add text into a .txt file. Although I have this completed I have a small problem. I need to write the string in the middle of the file more or less. Example:
Hello my name is Brandon,
I hope someone can help, //I want the string under this line.
Thank you.
Hopefully someone can help with a solution.
Edit Alright thanks guys, I'll try to figure it out, probably going to just rewrite the whole file. Ok well the program I am making is related to the hosts file, and not everyone has the same hosts file, so I was wondering if there is a way to read their hosts file, and copy all of it, while adding the string to it?

With regular files there's no way around it - you must read the text that follows the line you wish to append after, overwrite the file, and then append the original trailing text.
Think of files on disk as arrays - if you want to insert some items into the middle of an array, you need to shift all of the following items down to make room. The difference is that .NET offers convenience methods for arrays and Lists that make this easy to do. The file I/O APIs offer no such convenience methods, as far as I'm aware.
When you know in advance you need to insert in the middle of a file, it is often easier to simply write a new file with the altered content, and then perform a rename. If the file is small enough to read into memory, you can do this quite easily with some LINQ:
var allLines = File.ReadAllLines( filename ).ToList();
allLines.Insert( insertPos, "This is a new line..." );
File.WriteAllLines( filename, allLines.ToArray() );

This is the best method to insert a text in middle of the textfile.
string[] full_file = File.ReadAllLines("test.txt");
List<string> l = new List<string>();
l.AddRange(full_file);
l.Insert(20, "Inserted String");
File.WriteAllLines("test.txt", l.ToArray());

one of the trick is file transaction. first you read the file up to the line you want to add text but while reading keep saving the read lines in a separate file for example tmp.txt and then add your desired text to the tmp.txt (at the end of the file) after that continue the reading from the source file till the end. then replace the tmp.txt with the source file. at the end you got file with added text in the middle :)

Check out File.ReadAllLines(). Probably the easiest way.
string[] full_file = File.ReadAllLines("test.txt");
List<string> l = new List<string>();
l.AddRange(full_file);
l.Insert(20, "Inserted String");
File.WriteAllLines("test.txt", l.ToArray());

If you know the line index use readLine until you reach that line and write under it.
If you know exactly he text of that line do the same but compare the text returned from readLine with the text that you are searching for and then write under that line.
Or you can search for the index of a specified string and writ after it using th escape sequence \n.

As others mentioned, there is no way around rewriting the file after the point of the newly inserted text if you must stick with a simple text file. Depending on your requirements, though, it might be possible to speed up the finding of location to start writing. If you knew that you needed to add data after line N, then you could maintain a separate "index" of the offsets of line numbers. That would allow you to seek directly to the necessary location to start reading/writing.