Develop Reference

get a part of string from multiline/column string

Application .net C#
I have problem how to get out (on button click) this (rounded red) value from lista.txt file. In a fact, that's a exchange rate list. Values are changing daily.
Mine is always on the same position.
So far, using line.substring I've got the whole column inline:
5,2599355,3058300,2770031,0057322,4095196,1123050,8419020,7941597,0027418,7470806,9262237,4796281,729514
How do I get just a bold part. Its near end of string (7,479628).
Thanks a lot.

String.Split() should be able to do what you want.
if you already have the column it would be:
var array = column.Split('\t'); //assuming the separator is a tab

In the image it looks like the lines are tab seperated?
You could read each line then perform a split using the tab character....
string[] arsplit = line.Split('\t');
and then grab the item from the array based on index which I presume you'll know

Try something like this
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
namespace ConsoleApplication1
{
class Program
{
const string FILENAME = #"lista.txt";
static void Main(string[] args)
{
StreamReader reader = new StreamReader(FILENAME);
int lineCount = 0;
string inputline = "";
do while((inputline = reader.ReadLine()) != null)
{
if(++lineCount == 13)
{
string[] inputArray = inputline.Trim().Split(new char[] {' ','\t'},StringSplitOptions.RemoveEmptyEntries);
Console.WriteLine("Exchange Rate : '{0}'", inputArray[2]);
break;
}
}
}
}
}

I just received solution that works fine from one guy. His suggestion was to check for EUR which I'm interested for. So, after downloading file, approach is:
int counter = 0;
string line;
System.IO.StreamReader file = new System.IO.StreamReader(fullPath);
while ((line = file.ReadLine()) != null)
{
if (counter == 0)//jump first row, it's header don't need it
{
counter++;
continue;
}
if (line.Contains("EUR"))
{
line = line.Replace(" ", "");//clean spaces
line = line.Substring(3 + 3 + 3 + 8, 8);
Response.Write(line);
}
counter++;
}
file.Close();
So it maybe it can be useful for someone. In this moment I don't know which of your solutions is best. Just want to thank to all of you for help me in so short time.

Copy text to specific line

I didn't get why it isn't working..
Error shows like, newArraylist (line 13); newSreamReader (line 14, 24)
does not exist.
Any help will be appreciated.
using System;
using System.IO;
using System.Collections;
namespace InsertLineInTextFile
{
class Program
{
static void Main(string[] args)
{
string strTextFileName = "file.txt";
int iInsertAtLineNumber = 2;
string strTextToInsert = "Amudha";
ArrayList lines = new ArrayList();
StreamReader rdr = new StreamReader(strTextFileName);
string line;
while ((line = rdr.ReadLine()) != null) lines.Add(line);
rdr.Close();
if (lines.Count > iInsertAtLineNumber) lines.Insert(iInsertAtLineNumber, strTextToInsert);
else
lines.Add(strTextToInsert);
StreamWriter wrtr = new StreamWriter(strTextFileName);
foreach (string strNewLine in lines) wrtr.WriteLine(strNewLine);
wrtr.Close();
}
}
}

First, you have to think over what you're going to achieve; reverse engeniering (alas!) says
insert strTextToInsert at iInsertAtLineNumber line of fileName file
(or add the text if the file is too short)
Then implementation:
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
...
string fileName = "file.txt";
int iInsertAtLineNumber = 2;
string strTextToInsert = "Amudha";
List<String> lines = File
.ReadLines(fileName)
.ToList();
if (lines.Count > iInsertAtLineNumber)
lines.Insert(iInsertAtLineNumber, strTextToInsert);
else
lines.Add(strTextToInsert);
File.WriteAllLines(fileName, lines);
Please, do not use obsolete class ArrayList but List<T> (List<String> in the question). Often File.ReadLines and File.WriteAllLines are more readable and easier to maintain than StreamReader/StreamWriter.

Searching a file, only return strings with duplicates

Currently working on a project for a car park. I have a csv file which contains strings of information regarding car license plates. I have used regex already to return 90% of the license plates, however shorter personalised number plates aren;t returning correctly: ie "AA12" returns as "AA12BC" as it fits another regex.
Each string has two instances of the car license plate, is there a way to only return strings that prove correct for the regex and two instances of the number plate.
Code so far:
//start
using (TextReader reader = File.OpenText(#"C:\Users\user\documents\regdata.csv"))
{
List<string> lines = new List<string>();
string pattern = #"[A-Z]{3}[0-9]{3}";
string line;
while ((line = reader.ReadLine()) != null)
{
lines.Add(line);
}
List<string> regExs = new List<string>();
regExs.Add(#"[A-Z]{3}[0-9]{3}");
regExs.Add(#"[A-Z]{2}[0-9]{2}[A-Z]{3}");
regExs.Add(#"[A-Z]{1}[0-9]{3}[A-Z]{3}");
regExs.Add(#"[A-Z]{1}[0-9]{2}[A-Z]{3}");
regExs.Add(#"[A-Z]{1}[0-9]{1}[A-Z]{3}");
regExs.Add(#"[A-Z]{3}[0-9]{2,3}");
regExs.Add(#"[A-Z]{2}[0-9]{4}");
regExs.Add(#"[A-Z]{3}[0-9]{2}");
regExs.Add(#"[A-Z]{2}[0-9]{2}[A-Z]{3}");
using (StreamWriter writer = new StreamWriter(#"C: \Users\user\Desktop\usersNotes\plates.csv"))
{
foreach (var l in lines.Select(x => x.Split(',')[2]))
{
string result = "";
foreach (var r in regExs)
{
Regex myRegex = new Regex(r);
Match m = myRegex.Match(l);
if (m.Success)
{
result = m.Value;
break;
}
}
writer.WriteLine(l + "," + result);
}
Thanks

This should do it for you. I went ahead and coded (I think) the whole solution for you as I understand it. I made a Regex list rather than a string list; this way you don't have to build and tear down every Regex object with each loop.
Assumptions: (1) Plates never have " or , and (2) Plates don't show up more than twice.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.IO;
using System.Text;
using System.Windows.Forms;
using System.Text.RegularExpressions;
namespace DupeOnly {
public partial class Form1 : Form{
public Form1(){
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e){
string zRegData = File.ReadAllText(#"C:\Users\user\documents\regdata.csv");
HashSet<string> hsRegData = new HashSet<string>();
bool tfFirst = true;
string[] zAllPlateData = zRegData.Split(','); //License plates don't have comma's
List<Regex> rxList = new List<Regex>();
rxList.Add(new Regex(#"[A-Z]{3}[0-9]{3}"));
rxList.Add(new Regex(#"[A-Z]{2}[0-9]{2}[A-Z]{3}"));
rxList.Add(new Regex(#"[A-Z]{1}[0-9]{3}[A-Z]{3}"));
rxList.Add(new Regex(#"[A-Z]{1}[0-9]{2}[A-Z]{3}"));
rxList.Add(new Regex(#"[A-Z]{1}[0-9]{1}[A-Z]{3}"));
rxList.Add(new Regex(#"[A-Z]{3}[0-9]{2,3}"));
rxList.Add(new Regex(#"[A-Z]{2}[0-9]{4}"));
rxList.Add(new Regex(#"[A-Z]{3}[0-9]{2}"));
rxList.Add(new Regex(#"[A-Z]{2}[0-9]{2}[A-Z]{3}"));
Match m;
using (StreamWriter sw = new StreamWriter(#"C: \Users\user\Desktop\usersNotes\plates.csv")){
for(int Q = 0; Q < zAllPlateData.Length; Q++){
if(hsRegData.Add(zAllPlateData[Q]) == false){
//At this point we know it is a duplicate, must still match a check pattern
foreach(Regex rx in rxList){
m = rx.Match(zAllPlateData[Q]);
if(m.Success){
if(tfFirst){
tfFirst = false;
sw.Write(zAllPlateData[Q]); //First plate doesn't take a comma
}
else{
sw.Write("," + zAllPlateData[Q]); //Comma delimit subsequent plates
}
break;
}
}
}
}
}
}
}
}

How to accelerate buffering of output string?

This code times two methods of outputting a ~380Kb string:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Diagnostics;
namespace ConsoleApplication1
{
class Program
{
static string outbuff = "";
static void Main(string[] args)
{
{
Stopwatch exectime = new Stopwatch();
System.IO.StreamWriter file;
exectime.Reset(); exectime.Start();
file = new System.IO.StreamWriter("output.html");
for (int i = 0; i < 18000; i++)
{
outbuff += "444444444, 5555555555\n";
}
string fin = "\nString method took " + exectime.Elapsed.TotalSeconds + "s";
file.WriteLine(outbuff);
Console.WriteLine(fin);
file.WriteLine(fin);
file.Close();
}
{
Stopwatch exectime = new Stopwatch();
System.IO.StreamWriter file;
exectime.Reset(); exectime.Start();
file = new System.IO.StreamWriter("output2.html");
for (int i = 0; i < 18000; i++)
{
file.Write("444444444, 5555555555\n");
}
string fin = "\nDirect method took " + exectime.Elapsed.TotalSeconds + "s";
Console.WriteLine(fin);
file.WriteLine(fin);
file.Close();
}
}
}
}
String method took 2.2985349s
Direct method took 0.07191s
This is on a 3.5GHz CPU with 5Gb RAM.
I'm disappointed that simply buffering the output in a string is so costly!
In my real program, I need to deferr output until the string is assembled. Is there a faster way?

Yes, use a StringBuilder instead to assemble your string.
For an in-depth explanation for the performance boost see "Using the StringBuilder Class" - but basically because strings are immutable a new string is created when you concatenate, which is very expensive.

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;
}
}
}