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C# Read a row in a file

Given text file which contains the registration data like a database:
[ID] [Uname] [PW] [Email]
0 Aron asd asd#mail.com
1 Aron2 asdd asd#mail.com
I have the username and the password input.
How would i read only that line in this text file where my uname.Text and password.Text are given?

I agree with all the comments above. With the hypothesis that the file is not huge, you can simply load it all in memory and work on it:
//Load your files in a list of strings
IList<string> lines = File.ReadLines("\path\to\your\file.txt");
//Filter the list with only the pattern you want
var pattern = username + "[ ]{1,}" + password;
Regex regex = new Regex(pattern);
IList<string> results = lines.Where(x => regex.IsMatch(x)).ToList();
Here's a .NET fiddler that shows this.

If anyone have this problem too, this is my solve:
int check=0;
if (txt_uname.Text != "")
{
check = 0;
System.IO.StreamReader file = new System.IO.StreamReader(path);
string[] columnnames = file.ReadLine().Split('\t');
string newline;
while ((newline=file.ReadLine()) != null)
{
string[] values = newline.Split('\t');
if (check== 0){
for (int i = 0; i < values.Length; i++)
{
if (txt_uname.Text == values[i] && txt_pw.Text == values[i + 1])
{
Console.WriteLine("User found");
check= 1;
break;
}
else
{
Console.WriteLine("User isn't exists");
}
}
}
}

Try this:
var username = "Aron2";
var password = "asdd";
List<string> matchedValues; // Contains field values of matched line.
var lines = File.ReadLines("input.txt");
foreach (string l in lines)
{
var values = l.Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries).ToList();
if (values.Contains(username) && values.Contains(password))
{
matchedValues = values;
break; // Matching line found. No need to loop further.
}
}

Getting Data From IEnumerable

I have text file which contains airport Codes in this format:
"AAA","","Anaa Arpt","PF","","","AAA","2","N","272"
I used a StreamReader to to read the line from file and then I add that line to string list finally I convert that list to IEnumerable type.
Can you please help me how could I get only three values from each line for example
AAA is airportCode
Anna Arpt airport name
PF is country Code
I want to get only these three values from each row.
Please find below the code.
using (StreamReader sr = new StreamReader("C:/AirCodes/RAPT.TXT"))
{
String line;
while ((line = sr.ReadLine()) != null)
{
aircodesFromTravelPort.Add(line);
Console.WriteLine(line);
}
}
var codes = (IEnumerable<String>)aircodesFromTravelPort;
foreach (var aircode in codes)

It seems that you can try using Linq, something like that:
var codes = File
.ReadLines(#"C:/AirCodes/RAPT.TXT")
.Select(line => line.Split(','))
.Select(items => new {
// I've created a simple anonymous class,
// you'd probably want to create you own one
Code = items[0].Trim('"'), //TODO: Check numbers
Airport = items[2].Trim('"'),
Country = items[3].Trim('"')
})
.ToList();
...
foreach(var item in codes)
Console.WriteLine(item);

You'll probably want to make use of String's Split function on each line to get the values into an array.
while ((line = sr.ReadLine()) != null)
{
var values = line.Split(","); // here you have an array of strings containing the values between commas
var airportCode = values[0];
var airportName = values[2];
var airportCountry = values[3];
var airportInfo = airportCode + "," + airportName + "," + airportCountry;
aircodesFromTravelPort.Add(airportInfo );
// what you actually do with the values is up to you, I just tried to make it as close to the original as possible.
Console.WriteLine(airportInfo);
}
Hope this helps!

I like Regex with named groups:
var line = #"""AAA"","""",""Anaa Arpt"",""PF"","""","""",""AAA"",""2"",""N"",""272""";
var pattern = #"^""(?<airportCode>\w+)"",""(\w*)"",""(?<ariportName>[\w\s]+)"",""(?<cuntryCode>\w+)""";
Match match = Regex.Match(line, pattern, RegexOptions.IgnoreCase);
if (match.Success)
{
string airportCode = match.Groups["airportCode"].Value;
string ariportName = match.Groups["ariportName"].Value;
string cuntryCode = match.Groups["cuntryCode"].Value;
}

Scan multiple word from a text file

I have a list of words. I want the program to scan for multiple words from a text file.
This is what i already have:
int counter = 0;
string line;
StringBuilder sb = new StringBuilder();
string[] words = { "var", "bob", "for", "example"};
try
{
using (StreamReader file = new StreamReader("test.txt"))
{
while ((line = file.ReadLine()) != null)
{
if (line.Contains(Convert.ToChar(words)))
{
sb.AppendLine(line.ToString());
}
}
}
listResults.Text += sb.ToString();
}
catch (Exception ex)
{
listResults.ForeColor = Color.Red;
listResults.Text = "---ERROR---";
}
So i want to scan the file for a word, and if it's not there, scan for the next word...

String.Contains() only takes one argument: a string. What your call to Contains(Convert.ToChar(words)) does, is probably not what you expect.
As explained in Using C# to check if string contains a string in string array, you might want to do something like this:
using (StreamReader file = new StreamReader("test.txt"))
{
while ((line = file.ReadLine()) != null)
{
foreach (string word in words)
{
if (line.Contains(word))
{
sb.AppendLine(line);
}
}
}
}
Or if you want to follow your exact problem statement ("scan the file for a word, and if it's not there, scan for the next word"), you might want to take a look at Return StreamReader to Beginning:
using (StreamReader file = new StreamReader("test.txt"))
{
foreach (string word in words)
{
while ((line = file.ReadLine()) != null)
{
if (line.Contains(word))
{
sb.AppendLine(line);
}
}
if (sb.Length == 0)
{
// Rewind file to prepare for next word
file.Position = 0;
file.DiscardBufferedData();
}
else
{
return sb.ToString();
}
}
}
But this will think "bob" is part of "bobcat". If you don't agree, see String compare C# - whole word match, and replace:
line.Contains(word)
with
string wordWithBoundaries = "\\b" + word + "\\b";
Regex.IsMatch(line, wordWithBoundaries);

StringBuilder sb = new StringBuilder();
string[] words = { "var", "bob", "for", "example" };
string[] file_lines = File.ReadAllLines("filepath");
for (int i = 0; i < file_lines.Length; i++)
{
string[] split_words = file_lines[i].Split(' ');
foreach (string str in split_words)
{
foreach (string word in words)
{
if (str == word)
{
sb.AppendLine(file_lines[i]);
}
}
}
}

This works a treat:
var query =
from line in System.IO.File.ReadLines("test.txt")
where words.Any(word => line.Contains(word))
select line;
To get these out as a single string, just do this:
var results = String.Join(Environment.NewLine, query);
Couldn't be much simpler.
If you want to match only whole words it becomes only a little more complicated. You can do this:
Regex[] regexs =
words
.Select(word => new Regex(String.Format(#"\b{0}\b", Regex.Escape(word))))
.ToArray();
var query =
from line in System.IO.File.ReadLines(fileName)
where regexs.Any(regex => regex.IsMatch(line))
select line;

StreamReader case sensitive

My program currently reads a text file and compares it with the value in a text box and then tells me how many matches, this currently works.
My query is that it is case sensitive. Is there any way to make it so it doesn't matter whether it is in upper or lower case?
This is my code below:
if (!String.IsNullOrEmpty(CustodianEAddress.Text))
{
for (AddressLength1 = 0; AddressLength1 < Length; AddressLength1++)
{
List<string> list1 = new List<string>();
using (StreamReader reader = new StreamReader(FileLocation))
{
string line1;
//max 500
string[] LineArray1 = new string[500];
while ((line1 = reader.ReadLine()) != null)
{
list1.Add(line1); // Add to list.
if (line1.IndexOf(cust1[AddressLength1].ToString()) != -1)
{
count1++;
LineArray1[count1] = line1;
}
}
reader.Close();
using (System.IO.StreamWriter filed =
new System.IO.StreamWriter(FileLocation, true))
{
filed.WriteLine("");
filed.WriteLine("The email address " +
cust1[AddressLength1].ToString() + " was found " + count1 +
" times within the recipient's inbox");
}
string count1a;
count1a = count1.ToString();
}
}
}
else
{
MessageBox.Show("Please Enter an Email Address");
}
So basically, I need to compare the value in cust1[AddressLength1] with any values found in an array which is in the text file.

String.Compare() takes in an optional parameter that let's you specify whether or not the equality check should be case sensitive.
Edited in response to code being posted
Compare and Index of both take in an optional enumeration, StringComparison. If you choose StringComparison.OrdinalIgnoreCase then case will be ignored.

Here's a quick way to compare two strings without checking case:
string a;
string b;
string.Compare(a, b, true);
The true here is passed as the value of the ignoreCase parameter, meaning that upper and lower-case letters will be compared as if they were all the same case.
EDIT:
I've cleaned up your code a bit, and also put in the compare function. I included comments where I changed stuff:
// Not needed: see below. List<string> list1 = new List<string>();
using (StreamReader reader = new StreamReader(FileLocation))
{
string line1;
//max 500
List<string> LineArray1 = new List<string>();
while ((line1 = reader.ReadLine()) != null)
{
// list1.Add(line1); // Add to list.
// By adding to the list, then searching it, you are searching the whole list for every single new line - you're searching through the same elements multiple times.
if (string.Compare(line1, cust1[AddressLength1].ToString(), true) == 0)
{
// You can just use LineArray1.Count for this instead. count1++;
LineArray1.Add(line1);
}
}
// Not needed: using() takes care of this. reader.Close();
using (System.IO.StreamWriter filed =
new System.IO.StreamWriter(FileLocation, true))
{
filed.WriteLine(); // You don't need an empty string for a newline.
filed.WriteLine("The email address " +
cust1[AddressLength1].ToString() + " was found " + LineArray1.Count +
" times within the recipient's inbox");
}
string count1a;
count1a = LineArray1.Count.ToString();
}

The fact you are reading from a file or not it does not matter, when compare
use the static string Comapare function:
public static int Compare(
string strA,
string strB,
bool ignoreCase
)
and pass true as a last parameter.

C# Find if a word is in a document

I am looking for a way to check if the "foo" word is present in a text file using C#.
I may use a regular expression but I'm not sure that is going to work if the word is splitted in two lines. I got the same issue with a streamreader that enumerates over the lines.
Any comments ?

What's wrong with a simple search?
If the file is not large, and memory is not a problem, simply read the entire file into a string (ReadToEnd() method), and use string Contains()

Here ya go. So we look at the string as we read the file and we keep track of the first word last word combo and check to see if matches your pattern.
string pattern = "foo";
string input = null;
string lastword = string.Empty;
string firstword = string.Empty;
bool result = false;
FileStream FS = new FileStream("File name and path", FileMode.Open, FileAccess.Read, FileShare.Read);
StreamReader SR = new StreamReader(FS);
while ((input = SR.ReadLine()) != null)
{
firstword = input.Substring(0, input.IndexOf(" "));
if(lastword.Trim() != string.Empty) { firstword = lastword.Trim() + firstword.Trim(); }
Regex RegPattern = new Regex(pattern);
Match Match1 = RegPattern.Match(input);
string value1 = Match1.ToString();
if (pattern.Trim() == firstword.Trim() || value1 != string.Empty) { result = true; }
lastword = input.Trim().Substring(input.Trim().LastIndexOf(" "));
}

Here is a quick quick example using LINQ
static void Main(string[] args)
{
{ //LINQ version
bool hasFoo = "file.txt".AsLines()
.Any(l => l.Contains("foo"));
}
{ // No LINQ or Extension Methods needed
bool hasFoo = false;
foreach (var line in Tools.AsLines("file.txt"))
if (line.Contains("foo"))
{
hasFoo = true;
break;
}
}
}
}
public static class Tools
{
public static IEnumerable<string> AsLines(this string filename)
{
using (var reader = new StreamReader(filename))
while (!reader.EndOfStream)
{
var line = reader.ReadLine();
while (line.EndsWith("-") && !reader.EndOfStream)
line = line.Substring(0, line.Length - 1)
+ reader.ReadLine();
yield return line;
}
}
}

What about if the line contains football? Or fool? If you are going to go down the regular expression route you need to look for word boundaries.
Regex r = new Regex("\bfoo\b");
Also ensure you are taking into consideration case insensitivity if you need to.

You don't need regular expressions in a case this simple. Simply loop over the lines and check if it contains foo.
using (StreamReader sr = File.Open("filename", FileMode.Open, FileAccess.Read))
{
string line = null;
while (!sr.EndOfStream) {
line = sr.ReadLine();
if (line.Contains("foo"))
{
// foo was found in the file
}
}
}

You could construct a regex which allows for newlines to be placed between every character.
private static bool IsSubstring(string input, string substring)
{
string[] letters = new string[substring.Length];
for (int i = 0; i < substring.Length; i += 1)
{
letters[i] = substring[i].ToString();
}
string regex = #"\b" + string.Join(#"(\r?\n?)", letters) + #"\b";
return Regex.IsMatch(input, regex, RegexOptions.ExplicitCapture);
}