Split large file into smaller files by number of lines in C#?

Question

I am trying to figure out how to split a file by the number of lines in each file. THe files are csv and I can\'t do it by bytes. I need to do it by lines. 20k seems to be a goo

Answer 1

I'd do it like this:

// helper method to break up into blocks lazily

public static IEnumerable> SplitEnumerable
    (IEnumerable Sequence, int NbrPerBlock)
{
    List Group = new List(NbrPerBlock);

    foreach (T value in Sequence)
    {
        Group.Add(value);

        if (Group.Count == NbrPerBlock)
        {
            yield return Group;
            Group = new List(NbrPerBlock);
        }
    }

    if (Group.Any()) yield return Group; // flush out any remaining
}

// now it's trivial; if you want to make smaller files, just foreach
// over this and write out the lines in each block to a new file

public static IEnumerable> SplitFile(string filePath)
{
    return File.ReadLines(filePath).SplitEnumerable(20000);
}

Is that not sufficient for you? You mention moving from position to position,but I don't see why that's necessary.