如何使用C＃查找行中每个元素的数量并将每行的平均值存储在另一个数组中？

Question

I am using the below code to read data from a text file row by row. I would like to assign each row into an array. I must be able to find the number or rows/arrays and the number of elements on each one of them.

I would also like to do some manipulations on some or all rows and return their values.

I get the number of rows, but is there a way to to loop something like:

    *for ( i=1 to number of rows)
    do
    mean[i]<-row[i]
    done
    return mean*


var data = System.IO.File.ReadAllText("Data.txt");

var arrays = new List<float[]>();

var lines = data.Split(new[] {'\r', '\n'}, StringSplitOptions.RemoveEmptyEntries);

foreach (var line in lines)
{
    var lineArray = new List<float>();

    foreach (var s in line.Split(new[] {','}, StringSplitOptions.RemoveEmptyEntries))
    {
        lineArray.Add(Convert.ToSingle(s));
    }
    arrays.Add(lineArray.ToArray());

}

var numberOfRows = lines.Count();
var numberOfValues = arrays.Sum(s => s.Length);

Answer 1

var arrays = new List<float[]>();
//....your filling the arrays
var averages = arrays.Select(floats => floats.Average()).ToArray(); //float[]
var counts = arrays.Select(floats => floats.Count()).ToArray(); //int[]

Answer 2

Not sure I understood the question. Do you mean something like

foreach (string line in File.ReadAllLines("fileName.txt")
{
...
}

Answer 3

Is it ok for you to use Linq ? You might need to add using System.Linq; at the top.

float floatTester = 0;
List<float[]> result = File.ReadLines(@"Data.txt")
        .Where(l => !string.IsNullOrWhiteSpace(l))
        .Select(l => new {Line = l, Fields = l.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries) })
        .Select(x => x.Fields
                      .Where(f => Single.TryParse(f, out floatTester))
                      .Select(f => floatTester).ToArray())
        .ToList();

// now get your totals
int numberOfLinesWithData = result.Count;
int numberOfAllFloats = result.Sum(fa => fa.Length);

Explanation:

1. File.ReadLines reads the lines of a file (not all at once but straming)
2. Where returns only elements for which the given predicate is true(fe the line must contain more than empty text)
3. new { creates an anonymous type with the given properties(fe the fields separated by comma)
4. Then i try to parse each field to float
5. All that can be parsed will be added to an float[] with ToArray()
6. All together will be added to a List<float[]> with ToList()

Answer 4

Found an efficient way to do this. Thanks for your input everybody!

private void ReadFile()
    {
        var lines = File.ReadLines("Data.csv");
        var numbers = new List<List<double>>();
        var separators = new[] { ',', ' ' };
        /*System.Threading.Tasks.*/
        Parallel.ForEach(lines, line =>
        {
            var list = new List<double>();
            foreach (var s in line.Split(separators, StringSplitOptions.RemoveEmptyEntries))
            {
                double i;

                if (double.TryParse(s, out i))
                {
                    list.Add(i);
                }
            }

            lock (numbers)
            {
                numbers.Add(list);
            }
        });

        var rowTotal = new double[numbers.Count];
        var rowMean = new double[numbers.Count];
        var totalInRow = new int[numbers.Count()];

        for (var row = 0; row < numbers.Count; row++)
        {
            var values = numbers[row].ToArray();

            rowTotal[row] = values.Sum();
            rowMean[row] = rowTotal[row] / values.Length;
            totalInRow[row] += values.Length;
        }