Develop Reference

StreamWriter: Starting and ending on a specific line number

I would like to ask some tips and help on a reading/writing part of my C#.
Situation:
I have to read a CSV file; - OK
If the CSV file name starts with "Load_", I want to write on another CSV the data from line 2 to the last one;
If the CSV file name starts with "RO_", I want to write on 2 different CSVs, 1 with the line 1 to 4 and the other 4 to the last one;
What I have so far is:
public static void ProcessFile(string[] ProcessFile)
{
// Keeps track of your current position within a record
int wCurrLine = 0;
// Number of rows in the file that constitute a record
const int LINES_PER_ROW = 1;
int ctr = 0;
foreach (string filename in ProcessFile)
{
var sbText = new System.Text.StringBuilder(100000);
int stop_line = 0;
int start_line = 0;
// Used for the output name of the file
var dir = Path.GetDirectoryName(filename);
var fileName = Path.GetFileNameWithoutExtension(filename);
var ext = Path.GetExtension(filename);
var folderbefore = Path.GetFullPath(Path.Combine(dir, #"..\"));
var lineCount = File.ReadAllLines(#filename).Length;
string outputname = folderbefore + "output\\" + fileName;
using (StreamReader Reader = new StreamReader(#filename))
{
if (filename.Contains("RO_"))
{
start_line = 1;
stop_line = 5;
}
else
{
start_line = 2;
stop_line = lineCount;
}
ctr = 0;
while (!Reader.EndOfStream && ctr < stop_line)
{
// Add the text
sbText.Append(Reader.ReadLine());
// Increment our current record row counter
wCurrLine++;
// If we have read all of the rows for this record
if (wCurrLine == LINES_PER_ROW)
{
// Add a line to our buffer
sbText.AppendLine();
// And reset our record row count
wCurrLine = 0;
}
ctr++;
} // end of the while
}
int total_lenght = sbText.Length
// When all of the data has been loaded, write it to the text box in one fell swoop
using (StreamWriter Writer = new StreamWriter(dir + "\\" + "output\\" + fileName + "_out" + ext))
{
Writer.Write.(sbText.);
}
} // end of the foreach
} // end of ProcessFile
I was thinking about using the IF/ELSE: "using (StreamWriter Writer = new StreamWriter(dir + "\" + "output\" + fileName + "_out" + ext))" part. However, I am not sure how to pass, to StreamWriter, to only write from/to a specific line number.
Any Help is welcome! If I am missing some information, please, let me know (I am pretty new on stackoverflow).
Thank you.

Code is way too complicated
using System.Collections.ObjectModel;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
namespace ConsoleApplication57
{
class Program
{
static void Main(string[] args)
{
}
public static void ProcessFile(string[] ProcessFile)
{
foreach (string filename in ProcessFile)
{
// Used for the output name of the file
var dir = Path.GetDirectoryName(filename);
var fileName = Path.GetFileNameWithoutExtension(filename);
var ext = Path.GetExtension(filename);
var folderbefore = Path.GetFullPath(Path.Combine(dir, #"..\"));
var lineCount = File.ReadAllLines(#filename).Length;
string outputname = folderbefore + "output\\" + fileName;
using (StreamWriter Writer = new StreamWriter(dir + "\\" + "output\\" + fileName + "_out" + ext))
{
int rowCount = 0;
using (StreamReader Reader = new StreamReader(#filename))
{
rowCount++;
string inputLine = "";
while ((inputLine = Reader.ReadLine()) != null)
{
if (filename.Contains("RO_"))
{
if (rowCount <= 4)
{
Writer.WriteLine(inputLine);
}
if (rowCount == 4) break;
}
else
{
if (rowCount >= 2)
{
Writer.WriteLine(inputLine);
}
}
} // end of the while
Writer.Flush();
}
}
} // end of the foreach
} // end of ProcessFile
}
}

You can use LINQ to Take and Skip lines.
public abstract class CsvProcessor
{
private readonly IEnumerable<string> processFiles;
public CsvProcessor(IEnumerable<string> processFiles)
{
this.processFiles = processFiles;
}
protected virtual IEnumerable<string> GetAllLinesFromFile(string fileName)
{
using(var stream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read))
using(var reader = new StreamReader(stream))
{
var line = String.Empty;
while((line = reader.ReadLine()) != null)
{
yield return line;
}
}
}
protected virtual void ProcessFiles()
{
var sb1 = new StringBuilder();
var sb2 = new StringBuilder();
foreach(var file in this.processFiles)
{
var fileName = Path.GetFileNameWithoutExtension(file);
var lines = GetAllLinesFromFile(file);
if(fileName.StartsWith("RO_", StringComparison.InvariantCultureIgnoreCase))
{
sb1.AppendLine(lines.Take(4)); //take only the first four lines
sb2.AppendLine(lines.Skip(4).TakeWhile(s => !String.IsNullOrEmpty(s))); //skip the first four lines, take everything else
}
else if(fileName.StartsWith("Load_", StringComparison.InvariantCultureIgnoreCase)
{
sb2.AppendLine(lines.Skip(1).TakeWhile(s => !String.IsNullOrEmpty(s)));
}
}
// now write your StringBuilder objects to file...
}
protected virtual void WriteFile(StringBuilder sb1, StringBuilder sb2)
{
// ... etc..
}
}

How do I edit/replace a specific value in a .txt file using StreamWriter?

I have code in which I am reading in my .txt file. The text file contains values of first and last name, and a number.
"Daniel"
"Murrow"
"1234"
I am trying to use StreamWriter to edit a specific value. However, my code as of now edits the whole .txt file and replaces everything. I would only like to replace the number value in my case.
static classMates[] readClassMates(classMates[] classMateInfo)
{
StreamReader sr = new StreamReader(#"C:\Users\Callum\Documents\class.txt");
int count = 0;
while (!sr.EndOfStream)
{
classMateInfo[count].first = sr.ReadLine();
classMateInfo[count].last = sr.ReadLine();
string idTemp = sr.ReadLine();
classMateInfo[count].ID = Convert.ToInt32(idTemp);
count++;
}
sr.Close();
return classMateInfo;
static void editClassMates(classMates[] classMateInfo)
{
Console.Write("Who's number would you like to change? ");
string classMateInput = Console.ReadLine();
for (int i = 0; i < classMateInfo.Length; i++)
{
if (classMateInfo[i].last.Equals(classMateInput))
{
Console.Write("Enter new number: ");
string temp = Console.ReadLine();
int classMateNumber = Convert.ToInt32(temp);
StreamWriter sw = new StreamWriter(#"C:\Users\Callum\Documents\class.txt");
for (int j = 0; j < classMateInfo.Length; j++)
{
sw.WriteLine(classMateNumber);
}
sw.Close();
}
}
}
So my question is, how do I edit a specific value in my .txt file? I've tried my best, but I've been stuck on this for ages!

If the file is not very big (and therefore memory usage is not an issue) how about this:
var text = File.ReadAllText(#"C:\Users\Callum\Documents\class.txt");
var updatedText = text.Replace(...); // Do your string replacement here
File.WriteAllText(#"C:\Users\Callum\Documents\class.txt");

Counting number of words in a text file

I'm trying to count the number of words from a text file, namely this, to start.
This is a test of the word count program. This is only a test. If your
program works successfully, you should calculate that there are 30
words in this file.
I am using StreamReader to put everything from the file into a string, and then use the .Split method to get the number of individual words, but I keep getting the wrong value when I compile and run the program.
using System;
using System.IO;
class WordCounter
{
static void Main()
{
string inFileName = null;
Console.WriteLine("Enter the name of the file to process:");
inFileName = Console.ReadLine();
StreamReader sr = new StreamReader(inFileName);
int counter = 0;
string delim = " ,.";
string[] fields = null;
string line = null;
while(!sr.EndOfStream)
{
line = sr.ReadLine();
}
fields = line.Split(delim.ToCharArray());
for(int i = 0; i < fields.Length; i++)
{
counter++;
}
sr.Close();
Console.WriteLine("The word count is {0}", counter);
}
}

Try to use regular expression, e.g.:
int count = Regex.Matches(input, #"\b\w+\b").Count;

this should work for you:
using System;
using System.IO;
class WordCounter
{
static void Main()
{
string inFileName = null;
Console.WriteLine("Enter the name of the file to process:");
inFileName = Console.ReadLine();
StreamReader sr = new StreamReader(inFileName);
int counter = 0;
string delim = " ,."; //maybe some more delimiters like ?! and so on
string[] fields = null;
string line = null;
while(!sr.EndOfStream)
{
line = sr.ReadLine();//each time you read a line you should split it into the words
line.Trim();
fields = line.Split(delim.ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
counter+=fields.Length; //and just add how many of them there is
}
sr.Close();
Console.WriteLine("The word count is {0}", counter);
}
}

A couple hints.
What if you just have the sentence "hi" what would be your output?
Your counter calculation is: from 0 through fields.Length, increment counter. How are fields.Length and your counter related?

you're probably getting a one off error, try something like this
counter = 0;
while(!sr.EndOfStream)
{
line = sr.ReadLine();
fields = line.Split(delim.ToCharArray());
counter += field.length();
}
there is no need to iterate over the array to count the elements when you can get the number directly

using System.IO;
using System;
namespace solution
{
class Program
{
static void Main(string[] args)
{
var readFile = File.ReadAllText(#"C:\test\my.txt");
var str = readFile.Split(new char[] { ' ', '\n'}, StringSplitOptions.RemoveEmptyEntries);
System.Console.WriteLine("Number of words: " + str.Length);
}
}
}

//Easy method using Linq to Count number of words in a text file
/// www.techhowdy.com
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace FP_WK13
{
static class Util
{
public static IEnumerable<string> GetLines(string yourtextfile)
{
TextReader reader = new StreamReader(yourtextfile);
string result = string.Empty;
string line;
while ((line = reader.ReadLine()) != null)
{
yield return line;
}
reader.Close();
}
// Word Count
public static int GetWordCount(string str)
{
int words = 0;
string s = string.Empty;
var lines = GetLines(str);
foreach (var item in lines)
{
s = item.ToString();
words = words + s.Split(' ').Length;
}
return words;
}
}
}

How to read values from a comma separated file?

I want to read words in a text file of a line separated by commas in c sharp.
For example, I want to read this line:
9/10/2011 10:05,995.4,998.8,995.4,997.5,118000
and get the values: 9/10/2011 10:05, 995.4, 998.8, 995.4, 997.5 and 118000.
Next, I also need to change the format of the date to MMddYYYY, and of the time to HHmmss (e.g. 100500).
I am using this code for reading is there anything wrong
private void button1_Click(object sender, EventArgs e)
{
StreamReader reader1 = File.OpenText(Path1);
string str = reader1.ReadToEnd();
reader1.Close();
reader1.Dispose();
// File.Delete(Path1);
string[] Strarray = str.Split(new char[] { Strings.ChrW(7) });
int abc = Strarray.Length - 1;
int xyz = 0;
bool status = true;
while (xyz <= abc)
{
try
{
status = true;
string[] strarray1 = Strarray[xyz].Split(",".ToCharArray());
string SecName = strarray1[0];
int a2 = 0;
while (status) //If the selected list is empty or the text file has selected name this will execute
{
status = false;
string SecSym = strarray1[1];
int DT = int.Parse(strarray1[2]);
int TM = int.Parse(strarray1[3]);
float O = float.Parse(strarray1[2]);
float H = float.Parse(strarray1[3]);
float L = float.Parse(strarray1[4]);
float C = float.Parse(strarray1[5]);
double OI = double.Parse(Convert.ToString(0));
float V = float.Parse(strarray1[6]);
// string a = string.Concat(SecName, ",",SecSym,",", DT, ",", TM, ",", O, ",", H, ",", L);
//writer.WriteLine(a);
}
}
catch
{ }
}
}
}

.Net comes with a ready CSV parser you can use to get your data. It's a part of VB.net, but you can easily use it in C# by adding a reference to the assembly Microsoft.VisualBasic (it's OK, honesly), and a using statement: using Microsoft.VisualBasic.FileIO;.
The code should be simple to understand:
List<String[]> fileContent = new List<string[]>();
using(FileStream reader = File.OpenRead(#"data.csv")) // mind the encoding - UTF8
using(TextFieldParser parser = new TextFieldParser(reader))
{
parser.TrimWhiteSpace = true; // if you want
parser.Delimiters = new[] { "," };
parser.HasFieldsEnclosedInQuotes = true;
while (!parser.EndOfData)
{
string[] line = parser.ReadFields();
fileContent.Add(line);
}
}
CSV is fairly simple, but it may contain quoted values with commas and newlines, so using Split isn't the best option.

Use the String.Split method to get an array of strings:
string[] ar = line.Split(',')

This should get you started.
using System;
using System.IO;
public class Sample
{
public static void Main() {
using (StreamReader reader = new StreamReader("yourfile.txt")) {
string line = null;
while (null != (line = reader.ReadLine())) {
string[] values = line.Split(',');
DateTime date = DateTime.Parse(values[0];
float[] numbers = new float[values.Length - 1];
for (int i = 1; i < values.Length - 1; i++)
numbers[i - 1] = float.Parse(values[i]);
// do stuff with date and numbers
}
}
}
}
I have also posted a simple CsvReader class which may be helpful for you.

For a quick and simple solution, you can stream through the file and parse each line using String.Split like this:
using (var sr = File.OpenText("myfile.csv"))
{
string line;
while ((line = sr.ReadLine()) != null)
{
var fields = line.Split(',');
var date = DateTime.Parse(fields[0].Trim());
var value1 = fields[0].Trim();
}
}
However, this appraoch if fairly error prone, for a more robust solution check out the CsvReader project, it's excellent for parsing CSV files like this. It will handle field values with commas, trimming spaces before and after fields, and much more.
If you need to parse a date string from a format not recognised by DateTime.Parse, try using DateTime.ParseExact instead.

For 1st part of your task use Split method with , as separator. To convert string datetime from one format to another you need to convert that string to datetime(DateTime.Parse, DateTime.ParseExact) and then convert to final format using DateTime.ToString method.

rows contain your output
StreamReader sStreamReader = new StreamReader("File Path");
string AllData = sStreamReader.ReadToEnd();
string[] rows = AllData.Split(",".ToCharArray());

How to Access Variable From One Class in Another Class? [C#]

So I am working on a C# program that takes in a set of delimited text files within a directory and parses out the info within the files (i.e. the file path, file name, associated keywords). And this is what a sample file looks like...
C:\Documents and Settings\workspace\Extracted Items\image2.jpeg;image0;keyword1, keyword2, keyword3, keyword4
C:\Documents and Settings\workspace\Extracted Items\image3.jpeg;image1;keyword1, keyword2, keyword3, keyword4
C:\Documents and Settings\workspace\Extracted Items\image4.jpeg;image2;keyword1, keyword2, keyword3, keyword4
C:\Documents and Settings\workspace\Extracted Items\image5.jpeg;image3;keyword1, keyword2, keyword3, keyword4
Well I was given some code by my partner that does this, but I need to be able to access the list variable, that is populated within one of the methods. This is the code:
using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApp
{
public class FileIO
{
private static Boolean isTextFile;
private static Boolean debug;
private static int semiColonLoc1, semiColonLoc2, dblQuoteLoc1;
private static int lineLength, currentTagLength;
private static int numImages;
private static int numFiles;
public static List<Image> lImageSet;
/*
****************************************************
***** CHANGE THIS PATH TO YOUR PROPERTIES FILE *****
****************************************************
*/
private static readonly string propertiesFileDir = "C:/Documents and Settings/properties.properties";
public PropertyKeys getProperties(string propertiesFileDir, PropertyKeys aPropertyKeys)
{
string line;
string directoryKey = "extractedInfoDirectory";
string debugKey = "debug2";
string directory;
Boolean isDirectoryKey;
Boolean isDebugKey;
System.IO.StreamReader file = new System.IO.StreamReader(propertiesFileDir);
while ((line = file.ReadLine()) != null)
{
isDirectoryKey = false;
isDebugKey = false;
// If the current line is a certain length, checks the current line's key
if (line.Length > debugKey.Length)
{
isDebugKey = line.Substring(0, debugKey.Length).Equals(debugKey, StringComparison.Ordinal);
if (line.Length > directoryKey.Length)
{
isDirectoryKey = line.Substring(0, directoryKey.Length).Equals(directoryKey, StringComparison.Ordinal);
}
}
// Checks if the current line's key is the extractedInfoDirectory
if (isDirectoryKey)
{
directory = line.Substring(directoryKey.Length + 1);
aPropertyKeys.setExtractedInfoDir(directory);
}
// Checks if the current line's key is the debug2
else if (isDebugKey)
{
debug = Convert.ToBoolean(line.Substring(debugKey.Length + 1));
aPropertyKeys.setDebug(debug);
}
}
return aPropertyKeys;
}
public void loadFile()
{
string line;
string tempLine;
string fileToRead;
string fileRename;
string imagePath, imageName, imageTags, currentTag;
string extractedInfoDir;
string extension;
string textfile = "txt";
string[] filePaths;
PropertyKeys aPropertyKeys = new PropertyKeys();
// Finds extractedInfoDir and debug values
aPropertyKeys = getProperties(propertiesFileDir, aPropertyKeys);
extractedInfoDir = aPropertyKeys.getExtractedInfoDir();
debug = aPropertyKeys.getDebug();
// Finds all files in the extracted info directory
filePaths = Directory.GetFiles(extractedInfoDir);
numFiles = filePaths.Length;
// For each file in the directory...
for (int n = 0; n < numFiles; n++)
{
int k = filePaths[n].Length;
// Finds extension for the current file
extension = filePaths[n].Substring(k - 3);
// Checks if the current file is .txt
isTextFile = extension.Equals(textfile, StringComparison.Ordinal);
// Only reads file if it is .txt
if (isTextFile == true)
{
fileToRead = filePaths[n];
Console.WriteLine(fileToRead);
System.IO.StreamReader file = new System.IO.StreamReader(fileToRead);
// Reset variables and create a new lImageSet object
lImageSet = new List<Image>();
line = ""; tempLine = ""; imagePath = ""; imageName = ""; imageTags = ""; currentTag = "";
semiColonLoc1 = 0; semiColonLoc2 = 0; dblQuoteLoc1 = 0; lineLength = 0; currentTagLength = 0; numImages = 0;
while ((line = file.ReadLine()) != null)
{
// Creates a new Image object
Image image = new Image();
numImages++;
lineLength = line.Length;
// Finds the image path (first semicolon delimited field)
semiColonLoc1 = line.IndexOf(";");
imagePath = line.Substring(0, semiColonLoc1);
image.setPath(imagePath);
tempLine = line.Substring(semiColonLoc1 + 1);
// Finds the image name (second semicolon delimited field)
semiColonLoc2 = tempLine.IndexOf(";");
imageName = tempLine.Substring(0, semiColonLoc2);
image.setName(imageName);
tempLine = tempLine.Substring(semiColonLoc2 + 1);
// Finds the image tags (third semicolon delimited field)
imageTags = tempLine;
dblQuoteLoc1 = 0;
// Continues to gather tags until there are none left
while (dblQuoteLoc1 != -1)
{
dblQuoteLoc1 = imageTags.IndexOf("\"");
imageTags = imageTags.Substring(dblQuoteLoc1 + 1);
dblQuoteLoc1 = imageTags.IndexOf("\"");
if (dblQuoteLoc1 != -1)
{
// Finds the next image tag (double quote deliminated)
currentTag = imageTags.Substring(0, dblQuoteLoc1);
currentTagLength = currentTag.Length;
// Adds the tag to the current image
image.addTag(currentTag);
image.iNumTags++;
imageTags = imageTags.Substring(dblQuoteLoc1 + 1);
}
}
// Adds the image to the current image set
lImageSet.Add(image);
}
// Prints out information about what information has been stored
if (debug == true)
{
Console.WriteLine("Finished file " + (n + 1) + ": " + filePaths[n]);
for (int i = 0; i < numImages; i++)
{
Console.WriteLine();
Console.WriteLine("***Image " + (i + 1) + "***");
Console.WriteLine("Name: " + lImageSet.ElementAt(i).getName());
Console.WriteLine("Path: " + lImageSet.ElementAt(i).getPath());
Console.WriteLine("Tags: ");
for (int j = 0; j < lImageSet.ElementAt(i).iNumTags; j++)
{
Console.WriteLine(lImageSet.ElementAt(i).lTags.ElementAt(j));
}
}
}
file.Close();
// Changes destination file extension to .tmp
fileRename = fileToRead.Substring(0, fileToRead.Length - 4);
fileRename += ".tmp";
// Changes file extension to .tmp
System.IO.File.Move(fileToRead, fileRename);
}
// Not a text file
else
{
Console.WriteLine("Skipping file (no .txt extension)");
}
}
Console.ReadLine();
}
}
}
However, I don't want to mess with his code too much as he is not here for the time being to fix anything. So I just want to know how to access lImageSet from within his code in another class of mine. I was hoping it would be something like instantiating FileIO with FileIO fo = new FileIO, then doing something like fo.loadFile().lImageSet but that's not the case. Any ideas?

Since lImageSet is static, all you need to do to access it is:
List<image> theList = FileIO.lImageSet;
No instantiated object is necessary to get a reference to that field.

The list is static, so you access it with the name of the class:
List<Image> theList = FileIO.lImageSet

The loadFile method returns void, so you cannot use the dot operator to access anything from it. You'll want to do something like this:
FileIO fo = new FileIO();
fo.loadFile();
List<Image> theImages = FileIO.lImageSet;

It's public -- so from your class, you can just access it as:
FileIO.lImageSet
To get to the values in it, just iterate over it as:
//from FishBasketGordo's answer - load up the fo object
FileIO fo = new FileIO();
fo.loadFile();
foreach(var img in FileIO.lImageSet) {
//do something with each img item in lImageSet here...
}
EDIT: I built upon FishBasketGordo's answer by incorporating his loadFile() call into my sample.

Because lImageSet is static, so you don't need to instantiate FileIO to get it.
Try FileIO.lImageSet