So I have a generic number check that I am trying to implement:
public static bool isNumberValid(string Number)
{
}
And I want to read the contents of a textfile (only contains numbers) and check each line for the number and verify it is the valid number using isNumberValid. Then I want to output the results to a new textfile, I got this far:
private void button2_Click(object sender, EventArgs e)
{
int size = -1;
DialogResult result = openFileDialog1.ShowDialog(); // Show the dialog.
if (result == DialogResult.OK) // Test result.
{
string file = openFileDialog1.FileName;
try
{
string text = File.ReadAllText(file);
size = text.Length;
using (StringReader reader = new StringReader(text))
{
foreach (int number in text)
{
// check against isNumberValid
// write the results to a new textfile
}
}
}
catch (IOException)
{
}
}
}
Kind of stuck from here if anyone can help?
The textfile contains several numbers in a list:
4564
4565
4455
etc.
The new textfile I want to write would just be the numbers with true or false appended to the end:
4564 true
You don't need to read the entire file into memory all at once. You can write:
using (var writer = new StreamWriter(outputPath))
{
foreach (var line in File.ReadLines(filename)
{
foreach (var num in line.Split(','))
{
writer.Write(num + " ");
writer.WriteLine(IsNumberValid(num));
}
}
}
The primary advantage here is a much smaller memory footprint, as it only loads a small part of the file at a time.
You could try this to keep with the pattern you were initially following...
private void button1_Click(object sender, EventArgs e)
{
DialogResult result = openFileDialog1.ShowDialog(); // Show the dialog.
if (result == DialogResult.OK) // Test result.
{
string file = openFileDialog1.FileName;
try
{
using (var reader = new StreamReader(file))
{
using (var writer = new StreamWriter("results.txt"))
{
string currentNumber;
while ((currentNumber = reader.ReadLine()) != null)
{
if (IsNumberValid(currentNumber))
writer.WriteLine(String.Format("{0} true", currentNumber));
}
}
}
}
catch (IOException)
{
}
}
}
public bool IsNumberValid(string number)
{
//Whatever code you use to check your number
}
You need to replace your loop to look like this:
string[] lines = File.ReadAllLines(file);
foreach (var s in lines)
{
int number = int.Parse(s);
...
}
This would read each line of file, assuming that there is only one number per line,
and lines are separated with CRLF symbols. And parse each number to integer, assuming that integer is not greater than 2,147,483,647 and not less than -2,147,483,648, and integers are stored in your locale settings, with or without group separators.
In case if any line is empty, or contains non-integer - code will throw an exception.
You could try something like this:
FileStream fsIn = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);
using (StreamReader sr = new StreamReader(fsIn))
{
line = sr.ReadLine();
while (!String.IsNullOrEmpty(line)
{
line = sr.ReadLine();
//call isNumberValid on each line, store results to list
}
}
Then print the list using FileStream.
As other people have mentioned, your isNumberValid method could make use of the Int32.TryParse method, but since you said your text file only contains numbers this may not be necessary. If you're just trying to match the number exactly, you can use number == line.
First, load all lines of the input file in a string array,
then open the output file and loop over the array of strings,
Split each line at the space separator and pass every part to your static method.
The static method use Int32.TryParse to determine if you have a valid integer or not without throwing an exception if the input text is not a valid Int32 number.
Based on the result of the method write to the output file the desidered text.
// Read all lines in memory (Could be optimized, but for this example let's go with a small file)
string[] lines = File.ReadAllLines(file);
// Open the output file
using (StringWriter writer = new StringWriter(outputFile))
{
// Loop on every line loaded from the input file
// Example "1234 ABCD 456 ZZZZ 98989"
foreach (string line in lines)
{
// Split the current line in the wannabe numbers
string[] numParts = line.Split(' ');
// Loop on every part and pass to the validation
foreach(string number in numParts)
{
// Write the result to the output file
if(isNumberValid(number))
writer.WriteLine(number + " True");
else
writer.WriteLine(number + " False");
}
}
}
// Receives a string and test if it is a Int32 number
public static bool isNumberValid(string Number)
{
int result;
return Int32.TryParse(Number, out result);
}
Of course this works only if your definition of 'number' is equal to the allowed values for a Int32 datatype
Related
The text i am reading from has a couple lines.
I want to add new lines to it such as date, cost, intro.
I think I can manually enter it but I would like to know if it is possible to read each line and print it into the new file along with the new inputs on separate lines. Would like to use stream reader and stream writer still as it seems the simplest one I could find online.
The only thing it seems to print is: System.IO.StreamReader
//WRITE FILE
public void writeFile()
{
GroceryItem readGroceryList = new GroceryItem();
string[] lines = { "Grocery for you", Convert.ToString(DateTime.Now), readFile() };
StreamWriter file = new StreamWriter("c:\\MicrosoftVisual\\invoice.txt");
foreach (string line in lines)
{
file.WriteLine(line);
file.Flush();
}
}
public string readFile() // to adjust name of method later if require
{
//READ FILE
StreamReader myReader = new StreamReader("groceries.txt");
string consoleLine = "";
while (consoleLine != null)
{
consoleLine = myReader.ReadLine();
if (consoleLine != null)
{
return Convert.ToString(myReader);
}
}
return consoleLine;
}
public GroceryItem (string n, double p)
Your main problem lies in the readFile method. I think your intension is to read all lines and not just one line and then return your reader as string. To do this I would collect all the lines in a List<string> and return that, like so:
public List<string> ReadFile()
{
StreamReader myReader = new StreamReader("groceries.txt");
List<string> list = new List<string>(); // Create an empty list of strings
while (myReader.Peek() >= 0) // Checks if the stream has reacht the end of the file.
{
list.Add(myReader.ReadLine()); // Reads a line out of the files and appends it to the list.
}
return list; // Returns the list from the method.
}
With these changes you also need to adjust your writeFile method, like so:
public void WriteFile()
{
List<string> lines = ReadFile();
// Calls ReadFile to get the already exsisting lines from the file.
lines.Add("Grocery for you"); // You can add new lines now.
lines.Add(DateTime.Now.ToString());
StreamWriter file = new StreamWriter("c:\\MicrosoftVisual\\invoice.txt");
foreach (string line in lines)
{
file.WriteLine(line);
}
file.Flush(); // You only need to call Flush once when you are finished writing to the Stream.
}
There is even a simpler variant without Streams by using C#'s File helper class.
List<string> lines = new List<string>(File.ReadAllLines("groceries.txt"));
// Reads all lines from the file and puts them into the list.
lines.Add("Grocery for you"); // You can add new lines now.
lines.Add(DateTime.Now.ToString());
File.WriteAllLines("c:\\MicrosoftVisual\\invoice.txt", lines);
I have a problem reading data from a CSV file. As in the following example I try to read in the list information from two different columns. With the query "EndOfStream" or with a count variable larger than about 6000 I get the error: "The index was out of range". However, with a count variable of 4000, the code works exactly as it should. I do not understand my mistake.
List<string> gpsGGA = new List<string>();
List<string> gpsRMC = new List<string>();
public Form1()
{
InitializeComponent();
}
private void btn_file_Click(object sender, EventArgs e)
{
string path;
OpenFileDialog file = new OpenFileDialog();
if (file.ShowDialog() == DialogResult.OK)
{
try {
path = file.FileName;
StreamReader data = new StreamReader(path);
data.ReadLine(); //Header verwerfen
gpsGGA.Clear();
gpsRMC.Clear();
for(int i=0; i<8000; i++)//while (!data.EndOfStream)
{
string[] substring = data.ReadLine().Split(';');
gpsGGA.Add(substring[11]);
gpsRMC.Add(substring[12]);
}
data.Close();
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
Not sure why this is commented out:
for(int i=0; i<8000; i++)//while (!data.EndOfStream)
The while loop that is commented out intended to only read data while exists.
I added a using statement to ensure the file gets closed. I added an IsNullOrEmpty check in case there's a blank line at the end of the file, so you don't get an error with that.
using (StreamReader data = new StreamReader(path))
{
data.ReadLine(); //Header verwerfen
gpsGGA.Clear();
gpsRMC.Clear();
int counter = 0;
while (!data.EndOfStream)
{
string line = data.ReadLine();
if (! String.IsNullOrEmpty(line))
{
string[] substring = line.Split(';');
if ( substring.Length < 13 )
throw new ApplicationException("Malformated Data At Line " + counter.ToString());
gpsGGA.Add(substring[11]);
gpsRMC.Add(substring[12]);
}
counter += 1;
}
}
Your codes makes it hard to guess wheter the error is coming from reading the file or the file content itself.
You can use File.ReadAllLines which takes the file path and returns its lines as an array, regardless of the number of lines that you specify in the foor loop, which by the way can cause errors if the number of lines is is not equal to 8000.
if (file.ShowDialog() == DialogResult.OK)
{
try
{
gpsGGA.Clear();
gpsRMC.Clear();
string[] lines= File.ReadAllLines(file.FileName);
foreach(String line in lines)
{
string[] substring = line.Split(';');
gpsGGA.Add(substring[11]);
gpsRMC.Add(substring[12]);
}
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
The index was out of range is probably caused by some lines which have invalid data
For example this is line 6000 : sdd;dfdf;dfdf;00;dfdf;555
When you try to get element at index 11 or 12, it doesn't exist because this line has only 6 elements
I want to read a .txt file in c# and filter a line out of the string and only show that line. If the match is on the first line, i get a good output using streamreader.ReadLine. But if it's on the second line, i need to get it filtered. (i tought by creating a ReadLine loop?)
Thanks in advance
private void comboBox3_SelectedIndexChanged(object sender, EventArgs e)
{
StreamReader sr = new StreamReader(textBox1.Text);
string BoxLM1 = sr.ReadLine();
if (comboBox3.Text == "Anderlecht")
{
if (BoxLM1.Contains("Anderlecht"))
{
label5.Text = BoxLM1;
}
else
{
string BoxLM2 = sr.ReadToEnd();
MessageBox.Show(BoxLM2);
}
You can check all lines at once using File.ReadLines() method and LINQ:
var firstAnderlecht = File.ReadLines(textBox1.Text).FirstOrDefault(s => s.Contains("Anderlecht"));
if (firstAnderlecht != null) {
label5.Text = firstAnderlecht;
}
The ReadLines produces an enumerable of lines from the file; the FirstOrDefault method lets you apply a condition to all lines of the file without a loop, and pick the first line where the condition applies.
If you are manipulating big files i recommend to use this iterator:
private static IEnumerable FileIterator(String filePathe)
{
using (StreamReader streamReader = new StreamReader(filePathe))
{
String line;
while ((line = streamReader.ReadLine()) != null)
{
yield return line;
}
yield break;
}
}
it will prevent the loading of full file to RAM
I am rookie in C#, but I need solve one Problem.
I have several text files in Folder and each text files has this structure:
IdNr 000000100
Name Name
Lastname Lastname
Sex M
.... etc...
Load all files from Folder, this is no Problem ,but i need delete "zero" in IdNr, so delete 000000 and 100 leave there. After this file save. Each files had other IdNr, Therefore, it is harder :(
Yes, it is possible each files manual edit, but when i have 3000 files, this is not good :)
Can C# one algorithm, which could this 000000 delete and leave only number 100?
Thank you All.
Vaclav
So, thank you ALL !
But in the End I have this Code :-) :
using System.IO;
namespace name
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Browse_Click(object sender, EventArgs e)
{
DialogResult dialog = folderBrowserDialog1.ShowDialog();
if (dialog == DialogResult.OK)
TP_zdroj.Text = folderBrowserDialog1.SelectedPath;
}
private void start_Click(object sender, EventArgs e)
{
try
{
foreach (string file in Directory.GetFiles(TP_zdroj.Text, "*.txt"))
{
string text = File.ReadAllText(file, Encoding.Default);
text = System.Text.RegularExpressions.Regex.Replace(text, "IdNr 000*", "IdNr ");
File.WriteAllText(file, text, Encoding.Default);
}
}
catch
{
MessageBox.Show("Warning...!");
return;
}
{
MessageBox.Show("Done");
}
}
}
}
Thank you ALL ! ;)
You can use int.Parse:
int number = int.Parse("000000100");
String withoutzeros = number.ToString();
According to your read/save file issue, do the files contain more than one record, is that the header or does each record is a list of key and value like "IdNr 000000100"? It's difficult to answer without these informations.
Edit: Here's a simple but efficient approach which should work if the format is strict:
var files = Directory.EnumerateFiles(path, "*.txt", SearchOption.TopDirectoryOnly);
foreach (var fPath in files)
{
String[] oldLines = File.ReadAllLines(fPath); // load into memory is faster when the files are not really huge
String key = "IdNr ";
if (oldLines.Length != 0)
{
IList<String> newLines = new List<String>();
foreach (String line in oldLines)
{
String newLine = line;
if (line.Contains(key))
{
int numberRangeStart = line.IndexOf(key) + key.Length;
int numberRangeEnd = line.IndexOf(" ", numberRangeStart);
String numberStr = line.Substring(numberRangeStart, numberRangeEnd - numberRangeStart);
int number = int.Parse(numberStr);
String withoutZeros = number.ToString();
newLine = line.Replace(key + numberStr, key + withoutZeros);
newLines.Add(line);
}
newLines.Add(newLine);
}
File.WriteAllLines(fPath, newLines);
}
}
Use TrimStart
var trimmedText = number.TrimStart('0');
This should do it. It assumes your files have a .txt extension, and it removes all occurrences of "000000" from each file.
foreach (string fileName in Directory.GetFiles("*.txt"))
{
File.WriteAllText(fileName, File.ReadAllText(fileName).Replace("000000", ""));
}
These are the steps you would want to take:
Loop each file
Read file line by line
for each line split on " " and remove leading zeros from 2nd element
write the new line back to a temp file
after all lines processed, delete original file and rename temp file
do next file
(you can avoid the temp file part by reading each file in full into memory, but depending on your file sizes this may not be practical)
You can remove the leading zeros with something like this:
string s = "000000100";
s = s.TrimStart('0');
Simply, read every token from the file and use this method:
var token = "000000100";
var result = token.TrimStart('0');
You can write a function similar to this one:
static IEnumerable<string> ModifiedLines(string file) {
string line;
using(var reader = File.OpenText(file)) {
while((line = reader.ReadLine()) != null) {
string[] tokens = line.Split(new char[] { ' ' });
line = string.Empty;
foreach (var token in tokens)
{
line += token.TrimStart('0') + " ";
}
yield return line;
}
}
}
Usage:
File.WriteAllLines(file, ModifiedLines(file));
I have a log file that is not more than 10KB (File size can go up to 2 MB max) and I want to find if atleast one group of these strings occurs in the files. These strings will be on different lines like,
ACTION:.......
INPUT:...........
RESULT:..........
I need to know atleast if one group of above exists in the file. And I have do this about 100 times for a test (each time log is different, so I have reload and read the log), so I am looking for fastest and bets way to do this.
I looked up in the forums for finding the fastest way, but I dont think my file is too big for those silutions.
Thansk for looking.
I would read it line by line and check the conditions. Once you have seen a group you can quit. This way you don't need to read the whole file into memory. Like this:
public bool ContainsGroup(string file)
{
using (var reader = new StreamReader(file))
{
var hasAction = false;
var hasInput = false;
var hasResult = false;
while (!reader.EndOfStream)
{
var line = reader.ReadLine();
if (!hasAction)
{
if (line.StartsWith("ACTION:"))
hasAction = true;
}
else if (!hasInput)
{
if (line.StartsWith("INPUT:"))
hasInput = true;
}
else if (!hasResult)
{
if (line.StartsWith("RESULT:"))
hasResult = true;
}
if (hasAction && hasInput && hasResult)
return true;
}
return false;
}
}
This code checks if there is a line starting with ACTION then one with INPUT and then one with RESULT. If the order of those is not important then you can omit the if () else if () checks. In case the line does not start with the strings replace StartsWith with Contains.
Here's one possible way to do it:
StreamReader sr;
string fileContents;
string[] logFiles = Directory.GetFiles(#"C:\Logs");
foreach (string file in logFiles)
{
using (StreamReader sr = new StreamReader(file))
{
fileContents = sr.ReadAllText();
if (fileContents.Contains("ACTION:") || fileContents.Contains("INPUT:") || fileContents.Contains("RESULT:"))
{
// Do what you need to here
}
}
}
You may need to do some variation based on your exact implementation needs - for example, what if the word spans two lines, does the line need to start with the word, etc.
Added
Alternate line-by-line check:
StreamReader sr;
string[] lines;
string[] logFiles = Directory.GetFiles(#"C:\Logs");
foreach (string file in logFiles)
{
using (StreamReader sr = new StreamReader(file)
{
lines = sr.ReadAllLines();
foreach (string line in lines)
{
if (line.Contains("ACTION:") || line.Contains("INPUT:") || line.Contains("RESULT:"))
{
// Do what you need to here
}
}
}
}
Take a look at How to Read Text From a File. You might also want to take a look at the String.Contains() method.
Basically you will loop through all the files. For each file read line-by-line and see if any of the lines contains 1 of your special "Sections".
You don't have much of a choice with text files when it comes to efficiency. The easiest way would definitely be to loop through each line of data. When you grab a line in a string, split it on the spaces. Then match those words to your words until you find a match. Then do whatever you need.
I don't know how to do it in c# but in vb it would be something like...
Dim yourString as string
Dim words as string()
Do While objReader.Peek() <> -1
yourString = objReader.ReadLine()
words = yourString.split(" ")
For Each word in words()
If Myword = word Then
do stuff
End If
Next
Loop
Hope that helps
This code sample searches for strings in a large text file. The words are contained in a HashSet. It writes the found lines in a temp file.
if (File.Exists(#"temp.txt")) File.Delete(#"temp.txt");
String line;
String oldLine = "";
using (var fs = File.OpenRead(largeFileName))
using (var sr = new StreamReader(fs, Encoding.UTF8, true))
{
HashSet<String> hash = new HashSet<String>();
hash.Add("house");
using (var sw = new StreamWriter(#"temp.txt"))
{
while ((line = sr.ReadLine()) != null)
{
foreach (String str in hash)
{
if (oldLine.Contains(str))
{
sw.WriteLine(oldLine);
// write the next line as well (optional)
sw.WriteLine(line + "\r\n");
}
}
oldLine = line;
}
}
}