I have text file which consists of many rows and 18 columns of data seperated by tabs. I used this code and it is displaying entire data in single column. What I need is the data should be displayed in columns.
public static List<string> ReadDelimitedFile(string docPath)
{
var sepList = new List<string>();
// Read the file and display it line by line.
using (StreamReader file = new StreamReader(docPath))
{
string line;
while ((line = file.ReadLine()) != null)
{
var delimiters = new char[] { '\t' };
var segments = line.Split(delimiters, StringSplitOptions.RemoveEmptyEntries);
foreach (var segment in segments)
{
//Console.WriteLine(segment);
sepList.Add(segment);
}
}
file.Close();
}
// Suspend the screen.
Console.ReadLine();
return sepList;
}
You're outputting everything in one column like this (pseudo-code, to illustrate structure):
while (reading lines)
for (reading entries)
WriteLine(entry)
That is, for every line in the file and for every entry in that line, you output a new line. Instead, you want to only write a new line for every line in the file, and write the entries with separators (tabs?). Something more like this:
while (reading lines)
for (reading entries)
Write(entry)
WriteLine(newline)
That way all the entries for any given line in the file are on the same line in the output.
How you delimit those entries in the output is up to you, of course. And to write a carriage return could be as simple as Console.WriteLine(string.Empty), though I bet there are lots of other ways to do it.
18 columns would seem to be served best by using a dataGridView.
// Create your dataGrodView with the 18 columns using your designer.
int col = 0;
foreach (var segment in segments)
{
//Console.WriteLine(segment);
//sepList.Add(segment);
dataGridView1.Rows[whateverRow].Cells[col].Value = segment;
}
So according to your code, you have a following loop:
while{
<reads the lines one by one>
for each line{
<reading each segment and adding to the list.>
}
}
Your code read each segment of a line and append to the list. Ideally you should have 18 list for 18 columns. In java this problem can be solved with hashmaps:
Hashmap <String, ArrayList<String>> hmp = new Hashmap<String, ArrayList<String>>();`
while(read each line){
List<String> newList = new ArrayList<String>
foreach(segment as segments){
newList.add(segment);
}
hmp.put(column1,segment);
}
return hmp;
so you will have hmp.put(column2, segment), hmp.put(column3, segment) and so on.
Hope it helps.
You should be using DataTable or similar type for that but if you want to use List you can "emulate" rows and columns like this:
var rows = new List<List<string>>();
foreach(var line in File.ReadAllLines(docPath))
{
var columns = line.Split(new char[] { '\t' }, StringSplitOptions.RemoveEmptyEntries).ToList();
rows.Add(columns);
}
That will give you row/column like structure
foreach(var row in rows)
{
foreach(var column in row)
{
Console.Write(column + ",");
}
Console.WriteLine();
}
Related
I need to be able to rename the column in a spreadsheet from 'idn_prod' to 'idn_prod1', but there are two columns with this name.
I have tried implementing code from similar posts, but I've only been able to update both columns. Below you'll find the code I have that just renames both columns.
//locate and edit column in csv
string file1 = #"C:\Users\username\Documents\AppDevProjects\import.csv";
string[] lines = System.IO.File.ReadAllLines(file1);
System.IO.StreamWriter sw = new System.IO.StreamWriter(file1);
foreach(string s in lines)
{
sw.WriteLine(s.Replace("idn_prod", "idn_prod1"));
}
I expect only the 2nd column to be renamed, but the actual output is that both are renamed.
Here are the first couple rows of the CSV:
I'm assuming that you only need to update the column header, the actual rows need not be updated.
var file1 = #"test.csv";
var lines = System.IO.File.ReadAllLines(file1);
var columnHeaders = lines[0];
var textToReplace = "idn_prod";
var newText = "idn_prod1";
var indexToReplace = columnHeaders
.LastIndexOf("idn_prod");//LastIndex ensures that you pick the second idn_prod
columnHeaders = columnHeaders
.Remove(indexToReplace,textToReplace.Length)
.Insert(indexToReplace, newText);//I'm removing the second idn_prod and replacing it with the updated value.
using (System.IO.StreamWriter sw = new System.IO.StreamWriter(file1))
{
sw.WriteLine(columnHeaders);
foreach (var str in lines.Skip(1))
{
sw.WriteLine(str);
}
sw.Flush();
}
Replace foreach(string s in lines) loop with
for loop and get the lines count and rename only the 2nd column.
I believe the only way to handle this properly is to crack the header line (first string that has column names) into individual parts, separated by commas or tabs or whatever, and run through the columns one at a time yourself.
Your loop would consider the first line from the file, use the Split function on the delimiter, and look for the column you're interested in:
bool headerSeen = false;
foreach (string s in lines)
{
if (!headerSeen)
{
// special: this is the header
string [] parts = s.Split("\t");
for (int i = 0; i < parts.Length; i++)
{
if (parts[i] == "idn_prod")
{
// only fix the *first* one seen
parts[i] = "idn_prod1";
break;
}
}
sw.WriteLine( string.Join("\t", parts));
headerSeen = true;
}
else
{
sw.WriteLine( s );
}
}
The only reason this is even remotely possible is that it's the header and not the individual lines; headers tend to be more predictable in format, and you worry less about quoting and fields that contain the delimiter, etc.
Trying this on the individual data lines will rarely work reliably: if your delimiter is a comma, what happens if an individual field contains a comma? Then you have to worry about quoting, and this enters all kinds of fun.
For doing any real CSV work in C#, it's really worth looking into a package that specializes in this, and I've been thrilled with CsvHelper from Josh Close. Highly recommended.
I tried searching for a solution here but I can't seem to find any answers. I have a textfile that appears like this:
Nmr_test 101E-6 PASSED PASSED PASSED PASSED
Dc_volts 10V_100 CAL_+10V +9.99999000 +10.0000100 +9.99999740 +9.99999727
Dcv_lin 10V_6U 11.5 +0.0000E+000 +7.0000E+000 +2.0367E+001 +2.7427E+001
Dcv_lin 10V_6U 3 +0.0000E+000 +5.0000E+000 +1.3331E+001 +1.8872E+001
I have to convert this textfile to an Excel/xls file but I can't figure out how to insert them to the correct excel columns as they have different number of spaces in between columns. I've tried using this code below which is using space as a separator but it fails of course due to the varying number of spaces between the columns:
var lines = File.ReadAllLines(string.Concat(Directory.GetCurrentDirectory(), "\\Temp_textfile.txt"));
var rowcounter = 1;
foreach(var line in lines)
{
var columncounter = 1;
var values = line.Split(' ');
foreach(var value in values)
{
excelworksheet.Cells[rowcounter, columncounter] = new Cell(value);
columncounter++;
}
rowcounter++;
}
excelworkbook.Worksheets.Add(excelworksheet);
excelworkbook.Save(string.Concat(Directory.GetCurrentDirectory(), "\\Exported_excelfile.xls"));
Any advice?
EDIT: Got it working using SubString that selects each column using their fixed width.
I am new to C# and I am working with a .csv file which contains a lot of row just like this:
2014.02.02.;Name;Adress;Ft;24,32,46,13,15
2014.02.03.;Name;Adress;Ft;12,30,42,19,11,18
2014.02.03.;Name;Adress;Ft;61,32,44,42,22,17
2014.02.04.;Name;Adress;Ft;76,43,42,11,14 ....
Every line is similar, except the fact that after the "Ft;" there are 5 OR 6 numbers randomly.
I have written an application which reads the .CSV file and list it on the console.
Now all I need is to gather ONLY the numbers from the end of each line (which can be 5 or 6) and list only those to the console as new lines. (so the outfit would not change only the content)
I was not able to write this cycle, because the numbers of the number always changing randomly (5 or 6) and I am not sure how could I do that but I guess I need to use the substring.
Could you help me out with it? Thanks a lot!
How about:
var lines = File.ReadAllLines("Input.txt");
foreach (string line in lines)
{
var splitBySemiColon = line.Split(';');
List<int> numbersAtEnd = splitBySemiColon
.Last()
.Split(',')
.Select(s => int.Parse(s))
.ToList();
//do whatever you need to with numbersAtEnd... perhaps: foreach (int i in numbersAtEnd) Console.WriteLine(i)
}
foreach (var row in rows)
{
var lineElements = row.Split(';');
var numbers = lineElements.Last();
var lastNumber = numbers.Split(',').Last();
Console.WriteLine(lastNumber);
}
StreamReader sr=new Streameader("myFile.csv");
List<int> myNumbers=new List<int>();
using (sr)
{
while (!sr.EndOfStream)
{
string line=sr.Readline();
int index=line.LastIndexoF(';');
string numbers=sr.Substring(index+1,sr.Length-1-index);
string[] num=numbers.Split(',');
foreach (string n in num)
{
myNUmbers.Add(int.Parse(n));
}
}
}
If you sre storing each line in a string variable and there is a consistency as you have mentioned then following is the simplest way
string line = "2014.02.02.;Name;Adress;Ft;24,32,46,13,15";
string numbers = line.Substring(line.LastIndexOf(';') + 1);
var Lines = System.IO.File.ReadAllLines(#"c:\file.csv").Select( x => x.Split(';')).ToList();
Lines.ForEach(x => Console.WriteLine(string.Join("\t", x.Last().Split(','))));
output in console:
I've been working with some big delimited text (~1GB) files these days. It looks like somewhat below
COlumn1 #COlumn2#COlumn3#COlumn4
COlumn1#COlumn2#COlumn3 #COlumn4
where # is the delimiter.
In case a column is invalid I might have to remove it from the whole text file. The output file when Column 3 is invalid should look like this.
COlumn1 #COlumn2#COlumn4
COlumn1#COlumn2#COlumn4
string line = "COlumn1# COlumn2 #COlumn3# COlumn4";
int junk =3;
int columncount = line.Split(new char[] { '#' }, StringSplitOptions.None).Count();
//remove the [junk-1]th '#' and the value till [junk]th '#'
//"COlumn1# COlumn2 # COlumn4"
I's not able to find a c# version of this in SO. Is there a way I can do that? Please help.
EDIT:
The solution which I found myself is like below which does the job. Is there a way I could modify this to a better way so that it narrows down the performance impact it might have in case of large text files?
int junk = 3;
string line = "COlumn1#COlumn2#COlumn3#COlumn4";
int counter = 0;
int colcount = line.Split(new char[] { '#' }, StringSplitOptions.None).Length - 1;
string[] linearray = line.Split(new char[] { '#' }, StringSplitOptions.None);
List<string> linelist = linearray.ToList();
linelist.RemoveAt(junk - 1);
string finalline = string.Empty;
foreach (string s in linelist)
{
counter++;
finalline += s;
if (counter < colcount)
finalline += "#";
}
Console.WriteLine(finalline);
EDITED
This method can be very memory expensive, as your can read in this post, the suggestion should be:
If you need to run complex queries against the data in the file, the right thing to do is to load the data to database and let DBMS to take care of data retrieval and memory management.
To avoid memory consumption you should use a StreamReader to read file line by line
This could be a start for your task, missing your invalid match logic
using System.Collections.Generic;
using System.IO;
using System.Text;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
const string fileName = "temp.txt";
var results = FindInvalidColumns(fileName);
using (var reader = File.OpenText(fileName))
{
while (!reader.EndOfStream)
{
var builder = new StringBuilder();
var line = reader.ReadLine();
if (line == null) continue;
var split = line.Split(new[] { "#" }, 0);
for (var i = 0; i < split.Length; i++)
if (!results.Contains(i))
builder.Append(split[i]);
using (var fs = new FileStream("new.txt", FileMode.Append, FileAccess.Write))
using (var sw = new StreamWriter(fs))
{
sw.WriteLine(builder.ToString());
}
}
}
}
private static List<int> FindInvalidColumns(string fileName)
{
var invalidColumnIndexes = new List<int>();
using (var reader = File.OpenText(fileName))
{
while (!reader.EndOfStream)
{
var line = reader.ReadLine();
if (line == null) continue;
var split = line.Split(new[] { "#" }, 0);
for (var i = 0; i < split.Length; i++)
{
if (IsInvalid(split[i]) && !invalidColumnIndexes.Contains(i))
invalidColumnIndexes.Add(i);
}
}
}
return invalidColumnIndexes;
}
private static bool IsInvalid(string s)
{
return false;
}
}
}
First, what you will do is re-write the line to a text file using a 0-length string for COlumn3. Therefore the line after being written correctly would look like this:
COlumun1#COlumn2##COlumn4
As you can see, there are two delimiters between COlumn2 and COlumn4. This is a cell with no data in it. (By "cell" I mean one column of a certain, single row.) Later, when some other process reads this using the Split function, it will still create a new value for Column 3, but in the array generated by Split, the 3rd position would be an empty string:
String[] columns = stream_reader.ReadLine().Split('#');
int lengthOfThirdItem = columns[2].Length; // for proof
// lengthOfThirdItem = 0
This reduces invalid values to null and persists them back in the text file.
For more on String.Split see C# StreamReader save to Array with separator.
It is not possible to write to lines internal to a text file while it is also open for read. This article discusses it some (simultaneous read-write a file in C#), but it looks like that question-asker just wants to be able to write lines to the end. You want to be able to write lines at any point in the interior. I think this is not possible without buffering the data in some way.
The simplest way to buffer the data is rename the file to a temp file first (using File.CoMovepy() // http://msdn.microsoft.com/en-us/library/system.io.file.move(v=vs.110).aspx). Then use the temp file as the data source. Just open the temp file that to read in the data which may have corrupt entries, and write the data afresh to the original file name using the approach I describe above to represent empty columns. After this is complete, then you should delete the temp file.
Important
Deleting the temp file may leave you vulnerable to power and data transients (or software 'transients'). (I.e., a power drop that interrupts part of the process could leave the data in an unusable state.) So you may also want to leave the temp file on the drive as an emergency backup in case of some problem.
I'm trying to get the contents of a Text File, delete a line of string, and re-write back to the Text File, deleting the line of string. I'm using StreamReader to get the text, importing into a List, removing the string, then rewriting using StreamWriter. My problems arises somewhere around the removing or writing of the string. Instead of writing back the existing, non deleted contents to the text file, all the text is replaced with :
System.Collections.Generic.List`1[System.String]
My code for this function is as follows:
{
for (int i = deleteDevice.Count - 1; i >= 0; i--)
{
string split = "";
//deleteDevice[i].Split(',').ToString();
List<string> parts = split.Split(',').ToList();
if (parts.Contains(deviceList.SelectedItem.ToString()))
{
deleteDevice.Remove(i.ToString());
}
}
if (deleteDevice.Count != 0) //Error Handling
{
writer.WriteLine(deleteDevice);
}
}
deviceList.Items.Remove(deviceList.SelectedItem);
}
I would just like the script to write back any string that isn't deleted (If there is any), without replacing it. Any help is appreciated, Cheers
You can read all the info from the text file into a list and then remove from the list and rewrite that to the text file.
I would change the list 'deleteDevice' to store a string array instead and use the code below to determine which item to remove.
List<int> toRemove = new List<int>();
int i = 0;
/*build a list of indexes to remove*/
foreach (string[] x in deleteDevice)
{
if (x[0].Contains(deviceList.SelectedItem.ToString()))
{
toRemove.Add(i);
}
i++;
}
/*Remove items from list*/
foreach (int fd in toRemove)
deleteDevice.RemoveAt(fd);
/*write to text file*/
using (StreamWriter writer = new StreamWriter("Devices.txt"))
{
if (deleteDevice.Count != 0) //Error Handling
{
foreach (string[] s in deleteDevice)
{
StringBuilder sb = new StringBuilder();
for (int fds = 0; fds < s.Length; fds++ )
{
sb.Append(s[fds] + ",");
}
string line = sb.ToString();
writer.WriteLine(line.Substring(0, line.Length - 1));
}
}
}
This isn't the best solution but should work for your needs. There's probably a much easier way of doing this.
The problem is in the following line:
writer.WriteLine(deleteDevice);
You're writing deleteDevice (I assume this is of type List). List.ToString() returns the type name of the list, because this has no specific implementation. What you want is
foreach(String s in deleteDevice)
{
writer.WriteLine(s);
}
Problems
deleteDevice is of type List<string>, and because it also doesn't overload ToString(), the default behaviour of List<string>.ToString() is to return the name of the type.
Hence your line writer.WriteLine(deleteDevice); writes the string System.Collections.Generic.List1[System.String]`.
Other than that, there are many things wrong with your code...
For example, you do this:
string split = "";
and then on the line afterwards you do this:
List<string> parts = split.Split(',').ToList();
But because split is "", this will always return an empty list.
Solution
To simplify the code, you could first write a helper method that will remove from a file all the lines that match a specified predicate:
public void RemoveUnwantedLines(string filename, Predicate<string> unwanted)
{
var lines = File.ReadAllLines(filename);
File.WriteAllLines(filename, lines.Where(line => !unwanted(line)));
}
Then you can write the predicate something like this (this might not be quite right; I don't really know exactly what your code is doing because it's not compilable and omits some of the types):
string filename = "My Filename";
string deviceToRemove= deviceList.SelectedItem.ToString();
Predicate<string> unwanted = line =>
line.Split(new [] {','})
.Contains(deviceToRemove);
RemoveUnwantedLines(filename, unwanted);