Develop Reference

Assign line in text file to a string

I'm making a simple text adventure in C# and I was wondering if it was possible to read certain lines from a .txt file and assign them to a string.
I am aware of how to read all the text from a .txt file but how exactly would I assign the contents of certain lines to a string?

Have you considered the ReadAllLines method?
It returns an array of lines from which you can choose your desired line.
So for eg, if you wish to choose the 3rd line (Assuming you have 3 lines in the file):
string[] lines = File.ReadAllLines(path);
string myThirdLine= lines[2];

Probably the easiest (and cheapest in terms of memory consumption) is File.ReadLines:
String stringAtLine10 = File.ReadLines(path).ElementAtOrDefault(9);
Note that it is null if there are less than 10 lines in the file. See: ElementAtOrDefault.
It's just the concise version of a StreamReader and a counter variable which increases on every line.

As an advanced alternative: ReadLines plus some LINQ:
var lines = File.ReadLines(myFilePath).Where(MyCondition).ToArray();
where MyCondition:
bool MyCondition(string line)
{
if (line == "something")
{
return true;
}
return false;
}

In case you don't want to load all lines atonce
using(StreamReader reader=new StreamReader(path))
{
String line;
while((line=reader.ReadLine())!=null)//process temp
}

Here's a example how you can assign the lines to a string, you can't decide which line is which via fields, you have to select them yourself.
which is the line of the string you want to assign.
For example, you want line one, you define which as one and not zero, you want line eight, you define which with eight.
string getWord(int which)
{
string readed = "";
using (Systen.IO.StreamReader read = new System.IO.StreamReader("PATH HERE"))
{
readed = read.ReadToEnd();
}
string[] toReturn = readed.Split('\n');
return toReturn[which - 1];
}

Searching for text in a .txt

What would be the best way to search a text file that looks like this..?
efee|| Nbr| Address| Name |Phone|City|State|Zip abc
||455|gsgd |first last|gsg |fef |jk |0393 gjgj||jfj|ddg
|first last|fht |ree |hn |th ...more lines...
I started by reading in the file and all its contexts with a streamreader
I was thinking to count the "|" and grab the text between the 5th and 6th using substring but i'm not sure how to do the count of the "|". Or if someone has a better idea I'm open to it.
Tried something like this:
StreamReader file = new StreamReader(#"...");
string line;
int num=0;
while ((line = file.ReadLine()) != null)
{
for (int i = 1; i <= 6; i++)
{
if (line.Contains("|"))
{
num++;
}
}
int start = line.IndexOf("|");
int end = line.IndexOf("|");
string result = line.Substring(start, end - start - 1);
}
The text I want I beleive is always between the 5th and 6th "|"

You can do it like this:
var res = File
.ReadLines(#"FileName.txt")
.Select(line => line.Split(new[]{'|'}, StringSplitOptions.None)[5])
.ToList();
This produces a List<strings> from the file, where each string is the part of the corresponding line of the file taken from between the fifth and the sixth '|' separator.

For a delimited file you should use a parser - there is one in the Microsoft.VisualBasic.FileIO namespace - the TextFieldParser class, though you could also look at third-party libraries like the popular FileHelpers.
A simpler approach would be to use string.Split on the | character and getting the value in the corresponding index of the returned string[], however, if any of the fields are escaped and can validly contain | internally, this will fail.

You could split each line into an array:
while ((line = file.ReadLine()) != null)
{
var values = line.Split('|');
}

This should work
string txt = File.ReadAllText("file.txt");
string res = Regex.Match(txt, "\\|*?{5}(.+?)\\|", RegexOptions.Singleline).Result("$1");

C# read txt file and store the data in formatted array

I have a text file which contains following
Name address phone salary
Jack Boston 923-433-666 10000
all the fields are delimited by the spaces.
I am trying to write a C# program, this program should read a this text file and then store it in the formatted array.
My Array is as follows:
address
salary
When ever I am trying to look in google I get is how to read and write a text file in C#.
Thank you very much for your time.

You can use File.ReadAllLines method to load the file into an array. You can then use a for loop to loop through the lines, and the string type's Split method to separate each line into another array, and store the values in your formatted array.
Something like:
static void Main(string[] args)
{
var lines = File.ReadAllLines("filename.txt");
for (int i = 0; i < lines.Length; i++)
{
var fields = lines[i].Split(' ');
}
}

Do not reinvent the wheel. Can use for example fast csv reader where you can specify a delimeter you need.
There are plenty others on internet like that, just search and pick that one which fits your needs.

This answer assumes you don't know how much whitespace is between each string in a given line.
// Method to split a line into a string array separated by whitespace
private string[] Splitter(string input)
{
return Regex.Split(intput, #"\W+");
}
// Another code snippet to read the file and break the lines into arrays
// of strings and store the arrays in a list.
List<String[]> arrayList = new List<String[]>();
using (FileStream fStream = File.OpenRead(#"C:\SomeDirectory\SomeFile.txt"))
{
using(TextReader reader = new StreamReader(fStream))
{
string line = "";
while(!String.IsNullOrEmpty(line = reader.ReadLine()))
{
arrayList.Add(Splitter(line));
}
}
}

Searching strings in txt file

I have a .txt file with a list of 174 different strings. Each string has an unique identifier.
For example:
123|this data is variable|
456|this data is variable|
789|so is this|
etc..
I wish to write a programe in C# that will read the .txt file and display only one of the 174 strings if I specify the ID of the string I want. This is because in the file I have all the data is variable so only the ID can be used to pull the string. So instead of ending up with the example about I get just one line.
eg just
123|this data is variable|
I seem to be able to write a programe that will pull just the ID from the .txt file and not the entire string or a program that mearly reads the whole file and displays it. But am yet to wirte on that does exactly what I need. HELP!
Well the actual string i get out from the txt file has no '|' they were just in the example. An example of the real string would be: 0111111(0010101) where the data in the brackets is variable. The brackets dont exsist in the real string either.
namespace String_reader
{
class Program
{
static void Main(string[] args)
{
String filepath = #"C:\my file name here";
string line;
if(File.Exists(filepath))
{
StreamReader file = null;
try
{
file = new StreamReader(filepath);
while ((line = file.ReadLine()) !=null)
{
string regMatch = "ID number here"; //this is where it all falls apart.
Regex.IsMatch (line, regMatch);
Console.WriteLine (line);// When program is run it just displays the whole .txt file
}
}
}
finally{
if (file !=null)
file.Close();
}
}
Console.ReadLine();
}
}
}

Use a Regex. Something along the lines of Regex.Match("|"+inputString+"|",#"\|[ ]*\d+\|(.+?)\|").Groups[1].Value
Oh, I almost forgot; you'll need to substitute the d+ for the actual index you want. Right now, that'll just get you the first one.
The "|" before and after the input string makes sure both the index and the value are enclosed in a | for all elements, including the first and last. There's ways of doing a Regex without it, but IMHO they just make your regex more complicated, and less readable.

Assuming you have path and id.
Console.WriteLine(File.ReadAllLines(path).Where(l => l.StartsWith(id + "|")).FirstOrDefault());

Use ReadLines to get a string array of lines then string split on the |

You could use Regex.Split method

FileInfo info = new FileInfo("filename.txt");
String[] lines = info.OpenText().ReadToEnd().Split(' ');
foreach(String line in lines)
{
int id = Convert.ToInt32(line.Split('|')[0]);
string text = Convert.ToInt32(line.Split('|')[1]);
}

Read the data into a string
Split the string on "|"
Read the items 2 by 2: key:value,key:value,...
Add them to a dictionary
Now you can easily find your string with dictionary[key].

first load the hole file to a string.
then try this:
string s = "123|this data is variable| 456|this data is also variable| 789|so is this|";
int index = s.IndexOf("123", 0);
string temp = s.Substring(index,s.Length-index);
string[] splitStr = temp.Split('|');
Console.WriteLine(splitStr[1]);
hope this is what you are looking for.

private static IEnumerable<string> ReadLines(string fspec)
{
using (var reader = new StreamReader(new FileStream(fspec, FileMode.Open, FileAccess.Read, FileShare.Read)))
{
while (!reader.EndOfStream)
yield return reader.ReadLine();
}
}
var dict = ReadLines("input.txt")
.Select(s =>
{
var split = s.Split("|".ToArray(), 2);
return new {Id = Int32.Parse(split[0]), Text = split[1]};
})
.ToDictionary(kv => kv.Id, kv => kv.Text);
Please note that with .NET 4.0 you don't need the ReadLines function, because there is ReadLines
You can now work with that as any dictionary:
Console.WriteLine(dict[12]);
Console.WriteLine(dict[999]);
No error handling here, please add your own

You can use Split method to divide the entire text into parts sepparated by '|'. Then all even elements will correspond to numbers odd elements - to strings.
StreamReader sr = new StreamReader(filename);
string text = sr.ReadToEnd();
string[] data = text.Split('|');
Then convert certain data elements to numbers and strings, i.e. int[] IDs and string[] Strs. Find the index of the given ID with idx = Array.FindIndex(IDs, ID.Equals) and the corresponding string will be Strs[idx]
List <int> IDs;
List <string> Strs;
for (int i = 0; i < data.Length - 1; i += 2)
{
IDs.Add(int.Parse(data[i]));
Strs.Add(data[i + 1]);
}
idx = Array.FindIndex(IDs, ID.Equals); // we get ID from input
answer = Strs[idx];

is there any way to ignore reading in certain lines in a text file?

I'm trying to read in a text file in a c# application, but I don't want to read the first two lines, or the last line. There's 8 lines in the file, so effectivly I just want to read in lines, 3, 4, 5, 6 and 7.
Is there any way to do this?
example file
_USE [Shelley's Other Database]
CREATE TABLE db.exmpcustomers(
fName varchar(100) NULL,
lName varchar(100) NULL,
dateOfBirth date NULL,
houseNumber int NULL,
streetName varchar(100) NULL
) ON [PRIMARY]_
EDIT
Okay, so, I've implemented Callum Rogers answer into my code and for some reason it works with my edited text file (I created a text file with the lines I didn't want to use omitted) and it does exactly what it should, but whenever I try it with the original text file (above) it throws an exception. I display this information in a DataGrid and I think that's where the exception is being thrown.
Any ideas?

The Answer by Rogers is good, I am just providing another way of doing this.
Try this,
List<string> list = new List<string>();
using (StreamReader reader = new StreamReader(FilePath))
{
string text = "";
while ((text = reader.ReadLine()) != null)
{
list.Add(text);
}
list.RemoveAt(0);
list.RemoveAt(0);
}
Hope this helps

Why do you want to ignore exactly the first two and the last line?
Depending on what your file looks like you might want to analyze the line, e.g. look at the first character whether it is a comment sign, or ignore everything until you find the first empty line, etc.
Sometimes, hardcoding "magic" numbers isn't such a good idea. What if the file format needs to be changed to contain 3 header lines?
As the other answers demonstrate: Nothing keeps you from doing what you ever want with a line you have read, so of course, you can ignore it, too.
Edit, now that you've provided an example of your file: For your case I'd definitely not use the hardcoded numbers approach. What if some day the SQL statement should contain another field, or if it appears on one instead of 8 lines?
My suggestion: Read in the whole string at once, then analyze it. Safest way would be to use a grammar, but if you presume the SQL statement is never going to be more complicated, you can use a regular expression (still much better than using line numbers etc.):
string content = File.ReadAllText(filename);
Regex r = new Regex(#"CREATE TABLE [^\(]+\((.*)\) ON");
string whatYouWant = r.Match(content).Groups[0].Value;

Why not just use File.ReadAllLines() and then remove the first 2 lines and the last line? With such a small file speed differences will not be noticeable.
string[] allLines = File.ReadAllLines("file.ext");
string[] linesWanted = new string[allLines.Length-3];
Array.Copy(allLines, 2, linesWanted, 0, allLines.Length-3);

If you have a TextReader object wrapping the filestream you could just call ReadLine() two times.
StreamReader inherits from TextReader, which is abstract.
Non-fool proof example:
using (var fs = new FileStream("blah", FileMode.Open))
using (var reader = new StreamReader(fs))
{
reader.ReadLine();
reader.ReadLine();
// Do stuff.
}

string filepath = #"C:\whatever.txt";
using (StreamReader rdr = new StreamReader(filepath))
{
rdr.ReadLine(); // ignore 1st line
rdr.ReadLine(); // ignore 2nd line
string fileContents = "";
while (true)
{
string line = rdr.ReadLine();
if (rdr.EndOfStream)
break; // finish without processing last line
fileContents += line + #"\r\n";
}
Console.WriteLine(fileContents);
}

How about a general solution?
To me, the first step is to enumerate over the lines of a file (already provided by ReadAllLines, but that has a performance cost due to populating an entire string[] array; there's also ReadLines, but that's only available as of .NET 4.0).
Implementing this is pretty trivial:
public static IEnumerable<string> EnumerateLines(this FileInfo file)
{
using (var reader = file.OpenText())
{
while (!reader.EndOfStream)
{
yield return reader.ReadLine();
}
}
}
The next step is to simply skip the first two lines of this enumerable sequence. This is straightforward using the Skip extension method.
The last step is to ignore the last line of the enumerable sequence. Here's one way you could implement this:
public static IEnumerable<T> IgnoreLast<T>(this IEnumerable<T> source, int ignoreCount)
{
if (ignoreCount < 0)
{
throw new ArgumentOutOfRangeException("ignoreCount");
}
var buffer = new Queue<T>();
foreach (T value in source)
{
if (buffer.Count < ignoreCount)
{
buffer.Enqueue(value);
continue;
}
T buffered = buffer.Dequeue();
buffer.Enqueue(value);
yield return buffered;
}
}
OK, then. Putting it all together, we have:
var file = new FileInfo(#"path\to\file.txt");
var lines = file.EnumerateLines().Skip(2).IgnoreLast(1);
Test input (contents of file):
This is line number 1.
This is line number 2.
This is line number 3.
This is line number 4.
This is line number 5.
This is line number 6.
This is line number 7.
This is line number 8.
This is line number 9.
This is line number 10.
Output (of Skip(2).IgnoreLast(1)):
This is line number 3.
This is line number 4.
This is line number 5.
This is line number 6.
This is line number 7.
This is line number 8.
This is line number 9.

You can do this:
var valid = new int[] { 3, 4, 5, 6, 7 };
var lines = File.ReadAllLines("file.txt").
Where((line, index) => valid.Contains(index + 1));
Or the opposite:
var invalid = new int[] { 1, 2, 8 };
var lines = File.ReadAllLines("file.txt").
Where((line, index) => !invalid.Contains(index + 1));
If you're looking for a general way to remove the last and the first 2, you can use this:
var allLines = File.ReadAllLines("file.txt");
var lines = allLines
.Take(allLines.Length - 1)
.Skip(2);
But from your example it seems that you're better off looking for the string pattern that you want to read from the file. Try using regexes.