Question

is it possible to read csv file based on line. Like give a line number and it retrieves that particular line in CSV.

Thanks

Answer 1

If you just want to read a line of a text file(like csv), the easiest approach is using File.ReadLines and Enumerable.ElementAtOrDefault:

public static String getFileLine(String path, int indexOfLine)
{
    return File.ReadLines(path).ElementAtOrDefault(indexOfLine);
}

Use it in this way:

String line = getFileLine(@"C:\Temp\CsvFile.csv", 99);

That returns the 100th line (or null if there are less than 100 lines).

Here’s another similar method that returns a range of lines:

public static IEnumerable<String> getFileLines(String path, IEnumerable<int> lineIndices)
{
    return File.ReadLines(path).Where((l, i) => lineIndices.Contains(i));
}

return the first 10 lines:

IEnumerable<int> range = Enumerable.Range(0,10);
IEnumerable<String> lines = getFileLines(@"C:\Temp\CsvFile.csv", range);
foreach (String line in lines)
    Console.WriteLine(line);

Note that File.ReadLines is similar to a StreamReader, it does not read the whole file at once into memory(as FileReadAllLines), just as much as necessary.