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How to find average from multiple lines of a text file

I need to take a number from every line of a text file and find the average. I'm using stream reader to take the number out of a text file, I don't know where to go from here. Here's what I've done so far
using (StreamReader sr = new StreamReader("pupilSkiTimes.txt"))
{
string line = "";
while ((line = sr.ReadLine()) != null)
{
string[] components = line.Split("~".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
skiTime.Add(components[7]);
}
sr.Close();
}
How do I get this to read from every line of the text file, and once that's done, how do I get the average.
In case you need to know, the data I'm trying to read is doubles, e.g "23.43"

Here is how I will do it, as you mentioned in comments components[7] are double data that you read from the file.
We need to parse it to double, sum it up and divide it by the counting time we are able to parse the number in the file. If the number is not parsed and you want the total average of all lines then move the count out of the if statement.
using (StreamReader sr = new StreamReader("pupilSkiTimes.txt"))
{
string line;
double sum = 0;
int count = 0;
while ((line = sr.ReadLine()) != null)
{
string[] components = line.Split("~".ToCharArray(),
StringSplitOptions.RemoveEmptyEntries);
if (double.TryParse(components[7], out var result))
{
count++;
sum += result;
}
}
sr.Close();
var average = sum / count;
Console.WriteLine(average);
}

I think the handy method for this situation like this is useful hopefully you use it, I am using a similar this in my codes.
I am passing FilePath, Separator, and index value
static double getAvgAtIndex(string fPath, char seperator, int index)
{
double sum = 0;
int counter = 0;
using (StreamReader sr = new StreamReader(fPath))
{
string line = "";
while ((line = sr.ReadLine()) != null)
{
double rawData = 0;
string[] lineData = line.Split(seperator, StringSplitOptions.RemoveEmptyEntries);
double.TryParse(lineData[index], out rawData);
sum += rawData;
counter++;
}
sr.Close();
}
return sum / counter;
}
Usage of this,
static void Main(string[] args)
{
Console.WriteLine("The Avg is: {0}", getAvgAtIndex(#"..\myTextFile.txt", '~' ,1));
// The Avg is: 34.688
}

Here is how to use LINQ to clean up the code a bit
static class Program
{
static void Main(string[] args)
{
var data = File.ReadAllLines("pupilSkiTimes.txt")
.Select((line)=> line.Split("~".ToCharArray(), StringSplitOptions.RemoveEmptyEntries));
List<double> skiTime = new List<double>();
foreach (var parts in data)
{
if (double.TryParse(parts[7], out double x))
{
skiTime.Add(x);
}
}
double average = skiTime.Average();
}
}

Extract decimal/ integer values before a character sequence in C#

I want to extract all decimal/ integer value before a character sequence(am/AM) until an alphabet or a special charecter comes up value
Input Output
PEK\n2545 AMAzerbhaijan 2545
PEK\n2545 AMamorphous 2545
ANGwwquui\3.0 amAm 3.0
Awyu&&#^/Non-Prog//#*(*889/328.19 am -> 328.19
qii2781a/k28U28am 28
PEK\nam2545 AM 2545
Can I know what is the best possible way to do this? Thanks in advance.

Given the examples you showed, I believe this would do the trick:
public string ParseData(string input)
{
StringBuilder numberBuilder = new StringBuilder();
string terminatorChars = "am";
bool isCaseSensitive = false;
int terminatorCharLength = terminatorChars.Length;
for (int i = 0; i < input.Length; i++)
{
if (input.Length - i >= terminatorCharLength)
{
var currentSubstr = input.Substring(i, terminatorCharLength);
if ((currentSubstr == terminatorChars) || (!isCaseSensitive && currentSubstr.ToLowerInvariant() == terminatorChars.ToLowerInvariant()))
if(numberBuilder.Length>0)
return numberBuilder.ToString();
}
if (Char.IsDigit(input[i]) || input[i] == '.')
numberBuilder.Append(input[i]);
else if (Char.IsWhiteSpace(input[i]))
continue;
else
numberBuilder.Clear();
}
return null;
}

The data is fixed width data with name the first 50 character and value the data after column 50. See code below
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
namespace ConsoleApplication1
{
class Program
{
const string FILENAME = #"c:\temp\test.txt";
static void Main(string[] args)
{
StreamReader reader = new StreamReader(FILENAME);
string line = "";
List<KeyValuePair<string, decimal>> data = new List<KeyValuePair<string,decimal>>();
int lineNumber = 0;
while((line = reader.ReadLine()) != null)
{
if(++lineNumber > 1)
{
string key = line.Substring(0, 50).Trim();
decimal value = decimal.Parse(line.Substring(50));
data.Add(new KeyValuePair<string,decimal>(key,value));
}
}
}
}
}

Character Counter using Array List

I need to design a program that reads in an ASCII text file and creates an output file that contains each unique ASCII character and the number of times it appears in the file. Each unique character in the file must be represented by a character frequency class instance. The character frequency objects must be stored in an array list. My code is below:
using System.IO;
using System;
using System.Collections;
namespace ASCII
{
class CharacterFrequency
{
char ch;
int frequency;
public char getCharacter()
{
return ch;
}
public void setCharacter(char ch)
{
this.ch = ch;
}
public int getfrequency()
{
return frequency;
}
public void setfrequency(int frequency)
{
this.frequency = frequency;
}
static void Main()
{
string OutputFileName;
string InputFileName;
Console.WriteLine("Enter the file path");
InputFileName = Console.ReadLine();
Console.WriteLine("Enter the outputfile name");
OutputFileName = Console.ReadLine();
StreamWriter streamWriter = new StreamWriter(OutputFileName);
string data = File.ReadAllText(InputFileName);
ArrayList al = new ArrayList();
//create two for loops to traverse through the arraylist and compare
for (int i = 0; i < data.Length; i++)
{
int k = 0;
int f = 0;
for (int j = 0; j < data.Length; j++)
{
if (data[i].Equals(data[j]))
{
f++;
if (i > j) { k++; }
}
}
al.Add(data[i] + "(" + (int)data[i] + ")" + f + " ");
foreach (var item in al)
{
streamWriter.WriteLine(item);
}
}
streamWriter.Close();
}
}
}
When I run the program, the program does not stop running and the output file keeps getting larger until it eventually runs out memory and I get an error stating that. I am not seeing where the error is or why the loop won't terminate. It should just count the characters but it seems to keep looping and repeating counting the characters. Any help?

Try this approach :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace yourNamespace
{
class Char_frrequency
{
Dictionary<Char, int> countMap = new Dictionary<char, int>();
public String getStringWithUniqueCharacters(String input)
{
List<Char> uniqueList = new List<Char>();
foreach (Char x in input)
{
if (countMap.ContainsKey(x))
{
countMap[x]++;
}
else
{
countMap.Add(x, 1);
}
if (!uniqueList.Contains(x))
{
uniqueList.Add(x);
}
}
Char[] uniqueArray = uniqueList.ToArray();
return new String(uniqueArray);
}
public int getFrequency(Char x)
{
return countMap[x];
}
}
}
This might not be the ideal solution. But you can use these methods

How i count summary of numbers in a text file?

I did this code, but it doesnt give summary. Still I can get numbers of each row, but not summary...
using System;
using System.IO;
namespace Progaram
{
class Count
{
static void Main()
{
using (StreamReader sr = new StreamReader("file.txt"))
{
string[] numbers = File.ReadAllLines("file.txt");
int summary = 0;
for (int i = 0; i < numbers.Length; i++)
{
summary += numbers[i];
//Console.WriteLine(numbers[i]);
}
Console.WriteLine(summary);
sr.ReadLine();
}
}
}
}

Your current solution will not compile.
You'll receive the following compilation error:
Cannot convert type 'string' to 'int'.
You'll want to convert the parsed string into an int.
Also, you're using a StreamReader, and reading a single line after reading in all lines. You don't need the StreamReader in this case.
using System;
using System.IO;
namespace Progaram
{
class Count
{
static void Main()
{
string[] numbers = File.ReadAllLines("file.txt");
int summary = 0;
for (int i = 0; i < numbers.Length; i++)
{
summary += Convert.ToInt32(numbers[i]);
}
Console.WriteLine(summary);
}
}
}

You can't add a string to an int.
You need to either convert the entire string array to an int array with
int[] intNumbers = Array.ConvertAll(numbers, int.Parse);
Then index this array instead
summary += intNumbers[i];
Or as Michael suggests, convert numbers[i] before adding
summary += int.Parse(numbers[i]);

Text file only reading odd OR even lines?

I'm trying to write a little C# program that reads from a text file and lets you choose a line to print out.
For some reason, it will only print lines 1,3,5,etc.
If I change the bit that says int chooseLine = Convert.ToInt32(input); to int chooseLine = (int)Convert.ToInt64(input);, then it only prints even lines.(0,2,4,6,etc).
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
class Steve
{
public static int count = 0;
public static String[] steveTalk;
public static void Main()
{
using (StreamReader r = new StreamReader("Steve.txt"))
{
string line;
while ((line = r.ReadLine()) != null)
{
count++;
}
}
using (StreamReader sr = new StreamReader("Steve.txt"))
{
int i = 0;
steveTalk = new String[count];
String line;
while ((line = sr.ReadLine()) != null)
{
steveTalk[i] = line;
Console.WriteLine(steveTalk[i]);
i++;
}
}
while (true)
{
string input = Console.ReadLine();
int chooseLine = Convert.ToInt32(input);
try
{
Console.WriteLine(steveTalk[chooseLine]);
}
catch
{
Console.WriteLine("Error! Not a number or array index out of bounds");
}
Console.ReadLine();
}
}
}
Any ideas?

I'd like to suggest the System.IO.File.ReadAllLines(filename) method.
string []lines=System.IO.File.ReadAllLines("Steve.txt");
string input ;
while ((input = Console.ReadLine()) != "end")
{
int chooseLine;
int.TryParse(input,out chooseLine);
if(chooseLine<lines.Length)
{
Console.WriteLine(lines[chooseLine]);
}
}

There is no such problem with your code. What you might experience is that you have a Console.ReadLine() at the end of your loop, so if you enter a number it will show that line, then enter another number, that number will be ignored. Every other number that you enter will be ignored, which fits your description if you only tried to enter the numbers in sequence.
Here is some improvements to the code.
Use File.ReadAlLines to read the file.
Don't use exceptions unless you need it. You can easily check the input before any exception occurs.
Code:
using System;
using System.IO;
class Steve {
public static void Main() {
string[] lines = File.ReadAllLines("Steve.txt");
while (true) {
int line;
if (Int32.TryParse(Console.ReadLine(), out line)) {
if (line >= 0 && line < lines.Length) {
Console.WriteLine(lines[chooseLine]);
} else {
Console.WriteLine("Error! Array index out of bounds");
}
} else {
Console.WriteLine("Error! Not a number");
}
}
}
}