Working on an application to parse robots.txt. I wrote myself a method that pulled the the file from a webserver, and threw the ouput into a textbox. I would like the output to display a single line of text for every line thats in the file, just as it would appear if you were looking at the robots.txt normally, however the ouput in my textbox is all of the lines of text without carriage returns or line breaks. So I thought I'd be crafty, make a string[] for all the lines, make a foreach loop and all would be well. Alas that did not work, so then I thought I would try System.Enviornment.Newline, still not working. Here's the code as it sounds now....how can I change this so I get all the individual lines of robots.txt as opposed to a bunch of text cobbled together?
public void getRobots()
{
WebClient wClient = new WebClient();
string url = String.Format("http://{0}/robots.txt", urlBox.Text);
try
{
Stream data = wClient.OpenRead(url);
StreamReader read = new StreamReader(data);
string[] lines = new string[] { read.ReadToEnd() };
foreach (string line in lines)
{
textBox1.AppendText(line + System.Environment.NewLine);
}
}
catch (WebException ex)
{
MessageBox.Show(ex.Message, null, MessageBoxButtons.OK);
}
}
You are reading the entire file into the first element of the lines array:
string[] lines = new string[] {read.ReadToEnd()};
So all your loop is doing is adding the whole contents of the file into the TextBox, followed by a newline character. Replace that line with these:
string content = read.ReadToEnd();
string[] lines = content.Split(new string[] { "\r\n", "\n" }, StringSplitOptions.None);
And see if that works.
Edit: an alternative and perhaps more efficient way, as per Fish's comment below about reading line by line—replace the code within the try block with this:
Stream data = wClient.OpenRead(url);
StreamReader read = new StreamReader(data);
while (read.Peek() >= 0)
{
textBox1.AppendText(read.ReadLine() + System.Environment.NewLine);
}
You need to make the textBox1 multiline. Then I think you can simply go
textBox1.Lines = lines;
but let me check that
Try
public void getRobots()
{
WebClient wClient = new WebClient();
string robotText;
string[] robotLines;
System.Text.StringBuilder robotStringBuilder;
robotText = wClient.DownloadString(String.Format("http://{0}/robots.txt", urlBox.Text));
robotLines = robotText.Split(Environment.NewLine);
robotStringBuilder = New StringBuilder();
foreach (string line in robotLines)
{
robotStringBuilder.Append(line);
robotStringBuilder.Append(Environment.NewLine);
}
textbox1.Text = robotStringBuilder.ToString();
}
Try using .Read() in a while loop instead of .ReadToEnd() - I think you're just getting the entire file as one line in your lines array. Debug and check the count of lines[] to verify this.
Edit: Here's a bit of sample code. Haven't tested it, but I think it should work OK;
Stream data = wClient.OpenRead(url);
StreamReader read = new StreamReader(data);
List<string> lines = new List<string>();
string nextLine = read.ReadLine();
while (nextLine != null)
{
lines.Add(nextLine);
nextLine = read.ReadLine();
}
textBox1.Lines = lines.ToArray();
Related
I created a windows form application and I have a TextBox which has text as a file location like this : C:\DATA\FOLDER.
Also I have a text file in d:\data\test.txtwhich contains many lines but one defined line for Location="" .
How I can copy the location specified in the TextBox in the text file test.txt in the Location="" row, without mentioning the line number ?
You can do it in one line
var path = #"d:\data\test.txt";
File.WriteAllLines(path, File.ReadAllLines(path)
.Select(line => line.StartsWith("Location=\"")
? string.Format("Location=\"{0}\"", textBox1.Text)
: line));
First you read all lines in file and if any of them starts with "Location="" then it will be replaced by the location in text box. At the end you write the result back to the file.
If you don't like to do it in one line (and for me not getting downvoted for it) then you can just split it
var path = #"d:\data\test.txt";
var lines = File.ReadAllLines(path);
var modifiedLines = lines.Select(line =>
{
if (line.StartsWith("Location=\""))
{
return string.Format("Location=\"{0}\"", textBox1.Text);
}
else
{
return line;
}
});
File.WriteAllLines(path, modifiedLines);
I think sometimes writing more code reduces readability!
string text = File.ReadAllText("test.txt");
string filepath=textBox1.Text;
text = text.Replace("Location="" "," Location= "+filepath+");
File.WriteAllText("test.txt", text);
This works too:
IList<string> output = new List<string>();
using (StreamReader sr = new StreamReader("d:\\data\\test.txt"))
{
string line;
while ((line = sr.ReadLine()) != null)
{
if (line.StartsWith("Location=\""))
{
line = String.Format("Location=\"{0}\"", "TextBox.Text");
}
output.Add(line);
}
}
File.WriteAllText("d:\\data\\test.txt", string.Join(Environment.NewLine, output));
I want to write a string next to a line, randomly could be any line, also I want to know how to delete a line from it, here is how my StreamReader works:
using (StreamReader sb = new StreamReader("admin.txt"))
{
string[] ffoo = File.ReadAllLines("admin.txt");
string[] ppoof = ffoo[0].Split(';');
string line;
while ((line = sb.ReadLine()) != null)
{
if (line.StartsWith("#" + Server.Name.ToLower() + ": "))
{
string[] punch = line.Split(';');
if (!punch.Contains(Channel.Name.ToLower()))
{
StringBuilder str = new StringBuilder("admin.txt");
str.Append(Channel.Name.ToLower() + ";");
return;
}
}
}
Here is how the list is made:
#main: alien;nobody;somebody;
#devs: headdev;wae;
It reads it fine just it can't write something next to main channel, I mean I can only write a line or a string next to end of it which is on dev, and I want to write something on main, also I have some problems on how to delete an admin from main or dev. also this file would be oversize, maybe includes 500 lines at all after we use it, so please if you can give a solution for big files, thanks!
When calling StringBuilder.Append it appends to the end of the string.
When calling the StringBuilder(string) constructor it will append to the string passed as parameter for the constructor.
In this case you are passing "Admin.txt" as a string, but you really want to pass the content of Admin.txt, so you need to read the content of it.
This should do the trick:
string[] lines = File.ReadAllLines("admin.txt");
for (int i = 0; i < lines.Length; i++)
{
if (lines[i].StartsWith(string.Format("#{0}: ", Server.Name.ToLower()))
{
if (!lines[i].Split(';').Contains(Channel.Name.ToLower()))
lines[i] += ";" + Channel.Name.ToLower();
}
}
File.WriteAllLines("admin.txt", lines);
I'm sorry if I misunderstood what you wanted to do though.
I read the content of a CSV file from a zip file in memory(the requirment is not to write to disk) into the MemoryStream. and use to following code to get the human readable string
string result = Encoding.ASCII.GetString(memoryStream.ToArray());
However, we would like the result to be a string[] to map each row in the CSV file.
Is there a way to handle this automatically?
Thanks
Firstly, there's no need to call ToArray on the memory stream. Just use a StreamReader, and call ReadLine() repeatedly:
memoryStream.Position = 0; // Rewind!
List<string> rows = new List<string>();
// Are you *sure* you want ASCII?
using (var reader = new StreamReader(memoryStream, Encoding.ASCII))
{
string line;
while ((line = reader.ReadLine()) != null)
{
rows.Add(line);
}
}
You can use Split method to split string by newlines:
string[] result = Encoding.
ASCII.
GetString(memoryStream.ToArray()).
Split(new string[] { Environment.NewLine }, StringSplitOptions.None);
Depending on the contents of your CSV file, this can be a much harder problem than you're giving it credit for.
assume this is your csv:
id, data1, data2
1, some data, more data
2, "This element has a new line
right in the middle of the field", and that can create problems if you're reading line by line
If you simply read this in line by line with reader.ReadLine(), you're not going to get what you want if you happen to have quoted fields with new lines in the middle (which is generally allowed in CSVs). you need something more like this
List<String> results = new List<string>();
StringBuilder nextRow = new StringBuilder();
bool inQuote = false;
char nextChar;
while(reader.ReadChar(out nextChar)){ // pretend ReadChar reads a char into nextChar and returns false when it hits EOF
if(nextChar == '"'){
inQuote = !inQuote;
} else if(!inQuote && nextChar == '\n'){
results.Add(nextRow.ToString());
nextRow.Length = 0;
} else{ nextString.Append(nextChar); }
}
note that this handles double quotes. Missing quotes will be a problem, but they always are in .csv files.
Is it possible to replace the text in a text file with a new text without erasing the other data, here is my sample code, but its not working, I know there's a problem with it but I can't figure out, thanks,
private void button1_Click_1(object sender, EventArgs e)
{
StreamReader sr = new StreamReader("test10101.txt");
List<string> lines = new List<string>();
while (!sr.EndOfStream)
lines.Add(sr.ReadLine());
output = Convert.ToInt32(textBox1.Text);
newbal = Convert.ToInt32(lines[0]) - output;
MessageBox.Show("Please get your cash....\n\nYour new balance is: $" + newbal);
sr.Close();
{
string linetoreplace = lines[0];
int newlinevalue = newbal;
string contents = sr.ReadToEnd();
StreamWriter sw = new StreamWriter("test10101.txt" + ".tmp");
//contents = Regex.Replace(contents, linetoreplace, newlinevalue.ToString());
contents = contents.Replace(linetoreplace, newlinevalue.ToString());
sw.WriteLine(contents);
sw.Close();
}
I'm wondering if I use the Regex or directly replace the line,
You could do it a lot more easily:
string[] lines = System.IO.File.ReadAllLines("test");
lines[0] = /* replace with whatever you need */
System.IO.File.WriteAllLines("test", lines);
hope this helps
also I'd suggest using int.TryParse if you don't want an exception to be raised in your portion of code in case the first line of the file or the textbox values aren't numeric
if you really want to use the streamwriter you could go with this, also a simpler way:
line[0] = newbal.ToString();
foreach(string s in lines)
sw.WriteLine(s);
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;
}
}
}