Develop Reference

Use everything before a specific character

So, I've been learning C# and I need to remove everything after the
":" character.
I've used a StreamReader to read the text file, but then I can't use the Split function, then I tried it by using an int function to import it, but then again I can't use the Split function?
What I want this to do is import a text file that's written like;
name:lastname
name2:lastname2
And so that it only shows name and name2.
I've been searching this for a couple of days but I can't seem to figure it out!
I don't know what I'm doing wrong and how to import the text file without using StreamReader or anything else.
Edit:
I'm trying to post something to a website that goes like;
example.com/q=(name without ":")
Edit 2:
StreamReader list = new StreamReader(#"list.txt");
string reader = list.ReadToEnd();
string[] split = reader.Split(":".ToCharArray());
Console.WriteLine(split);
gives output as;
System.String[]

You've got a few issues here. First, use File.ReadLines() instead of a StreamReader, its much simpler and easier:
IEnumerable<string> lines = File.ReadLines("path/to/file");
Next, your lines variable needs to be iterated so you can get to each line of the collection:
foreach (string line in lines)
{
//TODO: write split logic here
}
Then you have to split each line on the ':' character:
string[] split = line.Split(":");
Your split variable is an array of string (i.e string[]) which means you have to access a specific index of the array if you want to see its value. This is your second issue, if you pass split to Console.WriteLine() under the hood it just calls .ToString() on the object you have passed it, and with a string[] it won't automatically give you all the values, you have to write that yourself.
So if your line variable was: "name:Steve", the split variable would have two indexes and look like this:
//split[0] = "name"
//split[1] = "Steve"
I made a fiddle here that demonstrates.

I your file size small and your name:lastname in one line use:
var lines = File.ReadAllLines("filaPath");
foreach (var line in lines)
{
var array = line.Split(':');
if (array.Length > 0)
{
var name = array[0];
}
}
if name:lastname isn't in new line tell me how it's seprated

How to add text to the line that starts with "hello" in a file

I have a file that contains many lines. There is a line here looking like below:
hello jim jack nina richi sam
I need to add a specific text salmon in this line and change it to below (it could be added anywhere in this line -end -begining - in the middle -doesnt matter ):
hello jim jack nina richi sam salmon
I tried:
string path = #"C:\testFolder\newTestLog.txt";
StreamReader myReader = new StreamReader(path);
string[] allLines = File.ReadAllLines(path);
foreach (string element in allLines) {
if (element.StartsWith("hello"))
{
Console.WriteLine(element);
}
}
myReader.Close();
}
Using this I'm able to read the file line by line and add each line to an array and print that line if that starts with "hello", but I'm not sure how to add text to this line

You should use what Joel answered it's nicer but if you're having trouble implementing it try this. After adding the salmon to the lines that start with hello you can overwrite the txt file by using File.WriteAllLines
string filePath = #"C:\testFolder\newTestLog.txt";
string[] allLines = File.ReadAllLines(filePath);
for(int i = 0; i < allLines.Length; i++)
{
if (allLines[i].StartsWith("hello"))
{
allLines[i] += " salmon";
}
}
File.WriteAllLines(filePath, allLines);

Try this:
string path = #"C:\testFolder\newTestLog.txt";
var lines = File.ReadLines(path).Select(l => l + l.StartsWith("hello")?" salmon":"");
foreach (string line in lines)
Console.WriteLine(line);
Note that this still only writes the results to the Console, as your sample does. It's not clear what you really want to happen with the output.
If you want this saved to the original file, you've opened up a small can of worms. Think of all of the data in your file as if it's stored in one contiguous block1. If you append text to any line in the file, that text has nowhere to go but to overwrite the beginning of the next. As a practical matter, if you need to modify file, this often means either writing out a whole new file, and then deleting/renaming when done, or alternatively keeping the whole file in memory and writing it all from start to finish.
Using the 2nd approach, where we keep everything in memory, you can do this:
string path = #"C:\testFolder\newTestLog.txt";
var lines = File.ReadAllLines(path).Select(l => l + l.StartsWith("hello")?" salmon":"");
File.WriteAllLines(path, lines);
1 In fact, a file may be split into several fragments on the disk, but even so, each fragment is presented to your program as part of a single whole.

Read text file and save numbers to intergers

I have a text file and I need to save specific items by type. So the numbers I have to save as integers and specific words as strings.
This is what I have so far:
string line;
int sizeOne;
int sizeTwo;
StreamReader file = new StreamReader(#"C:\Users\Asus\Documents\text.txt");
while ((line = file.ReadLine()) != null)
{
Console.WriteLine(line);
}
file.Close();
Console.ReadKey();
The .txt file is:
[header]
name = "Simple Maze"
size = 9,10
[/header]
[level]
xxxxxxxxx
x..xsx..x
x.xx.xx.x
x.......x
x..x.x..x
x..xxx..x
x.......x
x.xx.xx.x
x.x.t.x.x
xxxxxxxxx
[/level]

Since you are looping through the lines you can check at each line whether it Contains a certain string.
If you have found this line then you can twist the values that you need by using the String.Split method
If you have carved the values out of the file then you should Convert them to integer.
This is basically the algorithm in words. Now it's up to you to mould it into code.
You can find examples to each of the steps here on StackOverflow. Have fun

How to read barcode from text file by specified place in C#?

0000016011071693266104*014482*3 15301 45 VETRO NOVA BLUVETRO NOVA BLUE FLAT STRETCH 115428815150010050 05420 000033 0003
0000072011076993266101*014687*4 15300 45 VETRO NOVA BLUVETRO NOVA BLUE FLAT STRETCH 115428815160010030 05430 000032 0007
I have a text file which includes many barcode codes line by line, and as you see in above string format are company codes and others show other things.
So how can I get read this text line by line and character by character in C#?

For reading it line by line you can use a StreamReader - see for example on MSDN http://msdn.microsoft.com/en-us/library/db5x7c0d.aspx
Another option is:
string[] AllLines = File.ReadAllLines (#"C:\MyFile.txt");
This give you all lines in a string array and you can work with them - this uses more memory but is faster... see for example http://msdn.microsoft.com/en-us/library/s2tte0y1.aspx
When have a line in a string you can split that line for example:
string[] MyFields = AllLines[1].Split(null); // since your fields seem to be separated by whitespace
The result is that you have the parts of the line in an array and can access for example the second field in the line with MyFields[1] - see http://msdn.microsoft.com/en-us/library/b873y76a.aspx
EDIT - as per comment another option:
IF you exactly know the positions and lengths of your fields you can do this:
string MyIdentity = AllLines[1].SubString(1, 5);
For MSDN reference see http://msdn.microsoft.com/en-us/library/aka44szs.aspx

You use Microsoft libraries dedicated to files and streams to open a file, and Readline().
Then you use Microsoft libraries dedicated to parsing to parse those lines.
You create, with Microsoft libraries, a regular expression to detect bar codes (not borcod...)
Then you throw away anything that doesn't match your regular expression.
Then you compile and debug (you can use Mono). And voilà, you have a C# program that solves your problem.
Note: you definitely don't need to go "character by character". Microsoft libraries and parsing will be much easier for your simple need.

If all you are after is reading it line-by-line, and character-by-character, then this is a possible solution:
var lines = File.ReadLines(#"pathtotextfile.txt");
foreach (var line in lines)
{
foreach (var character in line)
{
char individualCharacter = character;
}
}
If you need to know which line and character you are on; you can use a for loop instead:
var lines = File.ReadAllLines(#"pathtotextfile.txt");
for (var i = 0; i < lines.Length; i++)
{
var line = lines[i];
for(var j = 0; j < line.Length; j++)
{
var character = line[j];
}
}
Or use SelectMany in LINQ:
var lines = File.ReadLines(#"pathtotextfile.txt");
foreach (char individualCharacter in lines.SelectMany(line => line))
{
}
Now, as far as my opinion goes, doing it "line by line" and "character by character" seems like a difficult choice to me. If you can tell us what exactly each bit of information is in the barcode, we could help you extract it that way.

Parsing a textfile in C# with skipping some contents

I'm trying to parse a text file that has a heading and the body. In the heading of this file, there are line number references to sections of the body. For example:
SECTION_A 256
SECTION_B 344
SECTION_C 556
This means, that SECTION_A starts in line 256.
What would be the best way to parse this heading into a dictionary and then when necessary read the sections.
Typical scenarios would be:
Parse the header and read only section SECTION_B
Parse the header and read fist paragraph of each section.
The data file is quite large and I definitely don't want to load all of it to the memory and then operate on it.
I'd appreciate your suggestions. My environment is VS 2008 and C# 3.5 SP1.

You can do this quite easily.
There are three parts to the problem.
1) How to find where a line in the file starts. The only way to do this is to read the lines from the file, keeping a list that records the start position in the file of that line. e.g
List lineMap = new List();
lineMap.Add(0); // Line 0 starts at location 0 in the data file (just a dummy entry)
lineMap.Add(0); // Line 1 starts at location 0 in the data file
using (StreamReader sr = new StreamReader("DataFile.txt"))
{
String line;
int lineNumber = 1;
while ((line = sr.ReadLine()) != null)
lineMap.Add(sr.BaseStream.Position);
}
2) Read and parse your index file into a dictionary.
Dictionary index = new Dictionary();
using (StreamReader sr = new StreamReader("IndexFile.txt"))
{
String line;
while ((line = sr.ReadLine()) != null)
{
string[] parts = line.Split(' '); // Break the line into the name & line number
index.Add(parts[0], Convert.ToInt32(parts[1]));
}
}
Then to find a line in your file, use:
int lineNumber = index["SECTION_B";]; // Convert section name into the line number
long offsetInDataFile = lineMap[lineNumber]; // Convert line number into file offset
Then open a new FileStream on DataFile.txt, Seek(offsetInDataFile, SeekOrigin.Begin) to move to the start of the line, and use a StreamReader (as above) to read line(s) from it.

Well, obviously you can store the name + line number into a dictionary, but that's not going to do you any good.
Well, sure, it will allow you to know which line to start reading from, but the problem is, where in the file is that line? The only way to know is to start from the beginning and start counting.
The best way would be to write a wrapper that decodes the text contents (if you have encoding issues) and can give you a line number to byte position type of mapping, then you could take that line number, 256, and look in a dictionary to know that line 256 starts at position 10000 in the file, and start reading from there.
Is this a one-off processing situation? If not, have you considered stuffing the entire file into a local database, like a SQLite database? That would allow you to have a direct mapping between line number and its contents. Of course, that file would be even bigger than your original file, and you'd need to copy data from the text file to the database, so there's some overhead either way.

Just read the file one line at a time and ignore the data until you get to the ones you need. You won't have any memory issues, but performance probably won't be great. You can do this easily in a background thread though.

Read the file until the end of the header, assuming you know where that is. Split the strings you've stored on whitespace, like so:
Dictionary<string, int> sectionIndex = new Dictionary<string, int>();
List<string> headers = new List<string>(); // fill these with readline
foreach(string header in headers) {
var s = header.Split(new[]{' '});
sectionIndex.Add(s[0], Int32.Parse(s[1]));
}
Find the dictionary entry you want, keep a count of the number of lines read in the file, and loop until you hit that line number, then read until you reach the next section's starting line. I don't know if you can guarantee the order of keys in the Dictionary, so you'd probably need the current and next section's names.
Be sure to do some error checking to make sure the section you're reading to isn't before the section you're reading from, and any other error cases you can think of.

You could read line by line until all the heading information is captured and stop (assuming all section pointers are in the heading). You would have the section and line numbers for use in retrieving the data at a later time.
string dataRow = "";
try
{
TextReader tr = new StreamReader("filename.txt");
while (true)
{
dataRow = tr.ReadLine();
if (dataRow.Substring(1, 8) != "SECTION_")
break;
else
//Parse line for section code and line number and log values
continue;
}
tr.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}