find max value

Question

i need to find max value within a file. This means finding max value within each 1000 values in a file, i.e., if there is 5000 values within a file then there should be 5 max values. Within first 1000 values: one max value, then within next 1000 values one more max value.... and so on.

# the size of the file will be unknown

# i had prepared a code for finding max value within first 1000 values in the file. I was thinking of iterating it, to get the desired results, but could not. The codes are as follows.

List<Double> list = new List<Double>();

StreamReader dat = new StreamReader(file path);

//int count = 1;

string dataline = "";

for (int i = 1; i <= dat.BaseStream.Length; i+=1000)

{

while ((dataline = dat.ReadLine()) != null)

{

Double sdat = Double.Parse(dataline);

list.Add(sdat);

richTextBox1.Text = list.Take(1000).Max().ToString();

}

}
please help!
Thank you.

Vulpes · Answer

OK try this: string[] datalines = File.ReadAllLines(filepath); int thousands = datalines.Length / 1000; int remainder = datalines.Length % 1000; string temp = ; for(int i = 0; i { temp += datalines.Select(s => double.Parse(s)) .Skip(i * 1000).Take(1000).Max().ToString() + 
; } if (remainder > 0) { temp += datalines.Select(s => double.Parse(s)) .Skip(thousands * 1000).Take(remainder).Max().ToString(); } richTextBox1.Text = temp;

csharp beginner · Answer

Vulpes you are awesome. Thank you.

csharp beginner · Answer

Vulpes Thank you so much for your effort. But what i want is to get all the max values in each 1000 values from the file at once on clicking the button in a list box or in a rich text box. Please provide a way if you could help.

Vulpes · Answer

If you load all 5000 values to start with you can use a combination of Skip and Take to find the maximum of each 1000 values. For example: richTextBox1.Text = list.Skip(1000).Take(1000).Max().ToString(); gets the maximum value of the elements 1001 to 2000 in the list.