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how to find average with strings c#

I need to set a variable as the average of 3 other variables, which are numbers but they are set as strings. How do I do this? I'm using c#, visual studio, windows forms.
The variable i'm trying to set is called skiTime, the variables i'm using to get the average are called skiTime1, skiTime2 and skiTime3.
basically i need the c# version of: skiTime = (skiTime1 + skiTime2 + skiTime3) / 3
The code where I start (declare? I don't know the word to use) the variables
List<string> skiTime1 = new List<string>();
List<string> skiTime2 = new List<string>();
List<string> skiTime3 = new List<string>();
string skiTime
The code where i set the value for the variables:
using (StreamReader sr = new StreamReader("pupilSkiTimes.txt"))
{
string line = "";
while ((line = sr.ReadLine()) != null)
{
string[] components = line.Split("~".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
skiTime1.Add(components[2]);
skiTime2.Add(components[3]);
skiTime3.Add(components[4]);
}
sr.Close();
}
I need to display skiTime1, skiTime2 and skiTime3 in a data grid view, so i think they need to be strings, if i'm not mistaken. skiTime will only be used in another calculation so maybe it can be turned into an int. I don't really know what i'm doing and only got this far because of tutorials, help.
I can post the whole code if this question is too confusing or doesn't have enough information.

public string CalculateAverage(List<string> skiTime1, List<string> skiTime2, List<string> skiTime3)
{
List<string> allValues = new List<string>();
allValues.AddRange(skiTime1);
allValues.AddRange(skiTime2);
allValues.AddRange(skiTime3);
float totalcount = 0;
float average = 0;
foreach (var value in allValues)
{
totalcount = totalcount + float.Parse(value);
}
average = totalcount / allValues.Count();
return average.ToString();
}
Function for returning the average value
Now call the function where u need like:
string skiTime = CalculateAverage(skiTime1, skiTime2, skiTime3);

You need to parse the strings to decimals then calculate the average:
List<decimal> avgTime = new List<decimal>();
for (var i = 0; i < skiTime1.Length; i++) {
var avg = (decimal.Parse(skiTime1[i]) + decimal.Parse(skiTime2[i]) + decimal.Parse(skiTime3[i])) / 3;
avgTime.Add(avg);
}

How to iterate through data and create a new text file every nth entries

I'm making a list of lines that need to be added to a .txt file (with tab delimitation). The text file needs to have a maximum of 500 entries plus a header.
Right now, I have this code, which is successfully iterating through my list and creating the text file with the header. If the file already exists, it appends the lines in my list without adding the header.
I can't quite figure out how to make a new file, add the header and add each line after my first file surpasses 500 entries.
Can you help me separate in 500 line files with headers? Thank you
This is the code I have so far:
var tab = new StringBuilder();
foreach (var line in textlinestoadd)
{
tab.AppendLine(line.ToString());
}
if (!File.Exists(textcsvpath))
{
string textheader = "Vendor\tDate\tInvoice\tPO\tTax\tTotal\tAcount\tType\tJobs\tClass" + Environment.NewLine;
File.WriteAllText(textcsvpath, textheader);
}
File.AppendAllLines(textcsvpath, textlinestoadd);

This seems like a good practice opportunity so I will leave the code part as exercise!
The basic idea is simple. Whenever you wrote 500 lines just reset and write to a new file
here is a high level pseudo code
Initialize StringBuilder sb
For each line do
Add line to sb
if line count == 500 then
save to file
reset sb
reset line count
update filename = next file
end if
End For
//writes the last chunk if # of lines is not multiple of 500
if line count is not 0 then
save to file
end if

I'd try something like this.
var tab = new StringBuilder();
int lineCount = 0;
string textheader = "Vendor\tDate\tInvoice\tPO\tTax\tTotal\tAcount\tType\tJobs\tClass" + Environment.NewLine;
if (File.Exists(textcsvpath)) {
FileStream fs = File.OpenRead(textcsvpath);
string[] fileContent = File.ReadAllLines(textcsvpath);
lineCount = fileContent.Length - 1; // assume the first line is the header
}
foreach (var line in textlinestoadd)
{
tab.AppendLine(line.ToString());
lineCount++;
if (lineCount > 0 && lineCount % 500 == 0)
{
if (!File.Exists(textcsvpath))
{
File.WriteAllText(textcsvpath, textheader);
}
File.AppendAllText(textcsvpath, tab.ToString());
tab.Clear();
textcsvpath = "some-new-file-name";
}
}
if (!File.Exists(textcsvpath))
{
File.WriteAllText(textcsvpath, textheader);
}
File.AppendAllText(textcsvpath, tab.ToString());
You'll need to do something to determine the new file name as you add a new file.

I'd do something like this:
const int limit = 500;
int iteration = 0;
string textHeader = "Vendor\tDate\tInvoice\tPO\tTax\tTotal\tAcount\tType\tJobs\tClass" + Environment.NewLine;
while(iteration * limit < textLinesToAdd.Count())
{
string fullPath = Path.Combine(filePath, $"{fileName}.{iteration}", extension);
IEnumerable<string> linesToAdd = textLinesToAdd.Skip(iteration++ * limit).Take(limit);
File.Create(fullPath);
File.WriteAllText(fullPath, textHeader);
File.AppendAllLines(fullPath, linesToAdd);
}
Define that filename as foo and the extension as bar, and you'll get a sequence of files called foo.0.bar, foo.1.bar, foo.2.bar and so on.

I'm assuming we want to create a file with the specified name, and then have some integer placed between the name and extension that increments every time a new file is created.
One way to do this would be to have a method that takes in a filePath string, a list of lines to write, a header string, and the maximum number of lines allowed per file. Then it could parse the directory of the file path, looking for a pattern related to the file name.
It would determine what the latest file name should be based on the contents of the directory and the number of lines in the last file that matches our pattern, then would write to that file until it was full, and then continue creating new files until the lines were all written.
Here's a sample class that can do that, where I added some helper methods to get a file's number, increment that number in the name, get the latest file from a directory, and write lines to the file. It also implements IComparer<string> so that we can pass it to OrderByDescending to easily sort the files we're interested in.
public class FileWriterHelper : IComparer<string>
{
public int Compare(string x, string y)
{
// Compare null
if (x == null) return y == null ? 0 : 1;
if (y == null) return -1;
// Compare count of parts split on '.'
var xParts = x.Split('.');
var yParts = y.Split('.');
if (xParts.Length < 3) return yParts.Length < 3 ? 0 : -1;
if (yParts.Length < 3) return 1;
// Compare numeric portion
int xNum, yNum;
if (int.TryParse(xParts[1], out xNum) &&
int.TryParse(yParts[1], out yNum))
{
return xNum.CompareTo(yNum);
}
// Unknown values
return string.Compare(x, y, StringComparison.Ordinal);
}
private static int? GetFileNumber(string fileName)
{
if (string.IsNullOrWhiteSpace(fileName)) return null;
var fileParts = fileName.Split('.');
int fileNum;
if (fileParts.Length < 3 || !int.TryParse(fileParts[1], out fileNum)) return null;
return fileNum;
}
private static string IncrementNumber(string fileName)
{
var number = GetFileNumber(fileName).GetValueOrDefault() + 1;
var fileParts = fileName.Split('.');
return $"{fileParts[0]}.{number}.{fileParts[fileParts.Length - 1]}";
}
private static string GetLatestFile(string filePath, int maxLines)
{
var fileDir = Path.GetDirectoryName(filePath);
var fileName = Path.GetFileNameWithoutExtension(filePath);
var fileExt = Path.GetExtension(filePath);
var latest = Directory.GetFiles(fileDir, $"{fileName}*{fileExt}")
.OrderByDescending(f => f, new FileWriterHelper())
.FirstOrDefault() ?? filePath;
return File.Exists(latest) && File.ReadAllLines(latest).Length >= maxLines
? Path.Combine(fileDir, IncrementNumber(Path.GetFileName(latest)))
: latest;
}
public static void WriteLinesToFile(string filePath, string header,
List<string> lines, int maxFileLines)
{
while ((lines?.Count ?? 0) > 0 && maxFileLines > 0)
{
var latestFile = GetLatestFile(filePath, maxFileLines);
if (!File.Exists(latestFile)) File.CreateText(latestFile).Close();
var lineCount = File.ReadAllLines(latestFile).Length;
if (lineCount == 0 && header != null)
{
File.WriteAllText(latestFile, string.Concat(header, Environment.NewLine));
lineCount = 1;
}
var numLinesToWrite = maxFileLines - lineCount;
File.AppendAllLines(latestFile, lines.Take(numLinesToWrite));
lines = lines.Skip(numLinesToWrite).ToList();
}
}
}
That was a bit of work, but now to use it is really simple:
private static void Main()
{
// Generate 5000 lines to write
var fileLines = Enumerable.Range(0, 5000).Select(i => $"Line number {i}").ToList();
// File path with base file name
var filePath = #"f:\public\temp\temp.csv";
// This should create 10 files
FileWriterHelper.WriteLinesToFile(filePath,
"HEADER: This should be the first line in each file.", fileLines, 500);
GetKeyFromUser("\nDone! Press any key to exit...");
}
If you run that once, it will create 10 files (because of the number of lines we're generating and the max number of lines per file we specified). And if you run it again, it will create 10 more, since we're using the same path and file name pattern, it recognizes the previous files that were in the location.
I'm sure it could use some work, but hopefully it's a start!

C# - how to monitor transaction activity for a banking application

I have been trying on a banking application code in which I want to monitor transaction activity where you read through a list of transaction records and return account nos that have exceeded the threshold amount for a given date.
For this I created a dummy text file using streamwriter where in I have the transaction records maintained spaced out with \t
For eg: AccountNumber\tTransactionDate\tTransactionAmount
When I read I am not sure how to split and collect distinct account nos for a given date and calculate the transaction amounts to further verify if its above the threshold amount.
Any help with this will be highly appreciated.
Thanks in advance.

You could split out the tabs to an array using split on the string you've read.
String Instr = "AccountNumber\tTransactionDate\tTransactionAmount";
char delim = '\t';
string[] array = Instr.Split(delim);
// array[0] = AccountNumber
// array[1] = TransactionDate
// array[2] = TransactionAmount

To build upon what Steve said, I would personally be inclined to deserialize the text into an object. Doing something like what I have below....
Now, instead of having just an array of text you could have an array of objects whose properties are the right types. Lots easier to do a date comparison... add up all of the amounts for a particular account when they're in plain old objects. At least, for me it is.
As a side note, what I have below is a pretty bad idea to do. But if you're just stubbing something out to replace it with something like a database access layer in the future, this could work in the short term.
Edit: If you're going to be storing data in plain text files, it would be much better to store them in a format that C# can handle. Something like JSON, and then use Newtonsoft.Json to serialize / deserialize or XML and use System.Xml.Serialization to serialize / deserialize the data.
class Program
{
static void Main(string[] args)
{
string srcfile = #"C:\Workspace\tmp\TestSTuff\bank\transactions.txt";
string transactionstr;
using (FileStream fs = new FileStream(srcfile, FileMode.Open, FileAccess.Read))
{
byte[] buffer = new byte[fs.Length];
int numtoread = (int)fs.Length;
int numread = 0;
while (numtoread > 0)
{
int n = fs.Read(buffer, numread, numtoread);
if (n == 0)
break;
numread += n;
numtoread -= n;
}
transactionstr = Encoding.Default.GetString(buffer);
}
char[] newline = { '\r','\n' };
char delim = ',';
string[] transactionstrs = transactionstr.Split(newline);
List<Transaction> transactions = new List<Transaction>();
foreach (var t in transactionstrs)
{
try
{
string[] fields = t.Split(delim);
DateTime.Parse(fields[1]);
transactions.Add(new Transaction
{
AccountNumber = int.Parse(fields[0]),
TransactionDate = DateTime.Parse(fields[1]),
TransactionAmount = double.Parse(fields[2])
});
}
catch
{
continue;
}
}
}
}
public class Transaction
{
public int AccountNumber { get; set; }
public DateTime TransactionDate { get; set; }
public double TransactionAmount { get; set; }
}

C# - Can't write list into the txt file

I have a problem with write list into txt file. If I run my Save method it makes only blank txt file. I fill this list from txt file and it works fine so I'm sure it isn't empty(I can see my appointments in calendar). There are my methods.
EDIT
Ok, I know where issue is. _appointments list in Load isn't the same of _appointments list in Save. I don't know why. I don't have any other lists. It's the same but it isn't :/
public bool Load()
{
DateTime start = new DateTime(2000,01,01);
CultureInfo enUS = new CultureInfo("en-US");
int length = 0;
string screenDiscription = "";
bool occursOnDate = false;
string line;
int i = 1;
StreamReader sr = new StreamReader("appointments.txt");
if (!File.Exists("appointments.txt"))
{
return false;
}
while ((line = sr.ReadLine()) != null)
{
if (i % 4 == 1)
{
start = DateTime.ParseExact(line, "ddMMyyyy HHmm", enUS);
}
if (i % 4 == 2)
{
length = int.Parse(line);
}
if (i % 4 == 3)
{
screenDiscription = line;
}
if (i % 4 == 0)
{
Appointment appointment = new Appointment(start, length, screenDiscription, occursOnDate);
_appointments.Add(appointment);
}
i++;
}
sr.Close();
return true;
}
public bool Save()
{
StreamWriter sw = new StreamWriter("appointments.txt");
if (File.Exists("appointments.txt"))
{
foreach(IAppointment item in _appointments)
{
sw.WriteLine(item.Start);
sw.WriteLine(item.Length);
sw.WriteLine(item.DisplayableDescription);
sw.WriteLine(" ");
}
sw.Close();
return true;
}
else
{
File.Create("appointments.txt");
foreach (IAppointment item in _appointments)
{
sw.WriteLine(item.Start);
sw.WriteLine(item.Length);
sw.WriteLine(item.DisplayableDescription);
sw.WriteLine(" ");
}
sw.Close();
return true;
}
}

I have refactored your Save method, but I'm unable to test it as I don't have your IAppointment and Appointment:
public void Save()
{
var builder = new StringBuilder()
foreach (IAppointment item in _appointments)
{
builder.AppendLine(item.Start);
builder.AppendLine(item.Length);
builder.AppendLine(item.DisplayableDescription);
builder.AppendLine(" ");
}
File.WriteAllText("appointments.txt", builder.ToString());
}
Note a few things here: I think your bool return type is superfluous since the method always returns true on all code paths; thus I've changed it to void. Also, I'm using a StringBuilder to construct the file contents, and then the built-in File.WriteAllText method which abstracts out the IO operations you would normally have to mess around with for opening the stream, the stream writer, closing, etc.
I'm not sure if this will resolve your issue because, as I stated, I can't test it and I'm not sure what exactly is wrong with the code you have, but at the very least it's probably a lot cleaner and easier to work with.

reading a .txt file and displaying numbers from the file

I am trying to read a .txt file using c# and displaying its contents but I am getting error as IndexOutOfRangeException with error code as 0xc000013a.
Here's my code:
static void Main(string[] args)
{
StreamReader sStreamReader = new StreamReader("d:\\TEST.txt");
while (!sStreamReader.EndOfStream)
{
string sLine = "";
if (sLine != null)
{
sLine = sStreamReader.ReadLine();
if (sLine != null)
{
string[] rows = sLine.Split(",".ToCharArray());
double a = Convert.ToDouble(rows[1]);
Console.Write(a);
int b = Convert.ToInt32(rows[3]);
Console.WriteLine(b);
Console.WriteLine();
}
}
}
}
my text file is as follows:
1,2,3,4,5,6,7
1,2,3,4,5,6,7
5,6,2,7,3,8,4
3,4,3,4,3
5,3,23,12
12,30000,12,99

I would change it to the following:
static void Main(string[] args)
{
// StreamReader is IDisposable which should be wrapped in a using statement
using (StreamReader reader = new StreamReader(#"d:\TEST.txt"))
{
while (!reader.EndOfStream)
{
string line = reader.ReadLine();
// make sure we have something to work with
if (String.IsNullOrEmpty(line)) continue;
string[] cols = line.Split(',');
// make sure we have the minimum number of columns to process
if (cols.Length < 4) continue;
double a = Convert.ToDouble(cols[1]);
Console.Write(a);
int b = Convert.ToInt32(cols[3]);
Console.WriteLine(b);
Console.WriteLine();
}
}
}
Some notes here:
StreamReader implements IDisposable, so you should wrap it in a using clause so that it is properly disposed of.
Don't name things like "sLine". That form of Hungarian is commonly recognized as seriously bad practice. Even Microsoft says don't do it.
You're dealing with columns, not rows. So that variable should be named appropriately.
Always test to make sure you have all of the columns you need before blindly accessing them.
Normally, I wouldn't use Convert.ToDouble or Convert.ToInt32. It's much safer to use TryParse to make sure it was able to convert. The code you have will blow if cols[1] and cols[3] had non-numeric data.
You can use the # symbol in front of a string to tell the compiler that it doesn't need to be escaped.
It's much cleaner to simply "continue" a loop instead of wrapping it in a if statement.
Setting a String variable to a blank string then immediately setting it to some other value causes the blank to stay in memory for the entire scope. In other words, it's wasting memory. Granted, in this case it's a micro-optimization, but it never hurts to use best practices all of the time.

Have you considered checking for row.Length before accessing row[1] and row[3]
I suspect your empty lines are the problem

Here is how you can do it simpler:
string[] lines = File.ReadAllLines("d:\\TEST.txt");
foreach (var line in lines.Where(line => line.Length > 0))
{
string[] numbers = line.Split(',');
// It checks whether numbers.Length is greater than
// 3 because if maximum index used is 3 (numbers[3])
// than the array has to contain at least 4 elements
if (numbers.Length > 3)
{
double a = Convert.ToDouble(numbers[1]);
Console.Write(a);
int b = Convert.ToInt32(numbers[3]);
Console.Write(b);
Console.WriteLine();
}
}

You should consider to use :
if (!string.IsNullOrEmpty(sLine))
instead of
if (sLine != null)
You have this exceptions because some lines are empty.
However, here is a way you should write your code when using a StreamReader :
using(var reader = new StreamReader(#"d:\\TEST.txt"))
{
string line;
while ((line= reader.ReadLine()) != null)
{
if (string.IsNullOrEmpty(line)) continue;
var rows = line.Split(",".ToCharArray());
var a = Convert.ToDouble(rows[1]);
Console.Write(a);
var b = Convert.ToInt32(rows[3]);
Console.WriteLine(b);
Console.WriteLine();
}
}
Regards,
Kévin