Add Count() to FileInfo

[adamfisher]

This issue is a proposal to add Count() to FileInfo to provide the ability to count the total number of lines in a file (no filter specified) or count the specific number of occurrences of a string in a file (using the filter).

/// <summary>
/// Gets the total number of lines in a file.
/// Note this method is optimized for large files and must count each line so it may be expensive for large files.
/// </summary>
/// <param name="this">The file to perform the count on.</param>
/// <param name="filter">If specified, finds the number of concurrences of the string in the file.</param>
/// <returns>
/// A count of the number of lines in the file.
/// </returns>
public static long Count(this FileInfo @this, string filter = null)
{
	using (var reader = @this.OpenText())
	{
		var count = 0L;

		if (filter == null)
		{
			while (!reader.EndOfStream)
			{
				reader.ReadLine();
				count++;
			}
		}
		else
		{
			while (!reader.EndOfStream)
			{
				var line = reader.ReadLine();

				if(line != null && line.Contains(filter))
					count++;
			}
		}

		return count;
	}
}

[JonathanMagnan]

Hello @adamfisher ,

We are now back from holiday and started to look at your suggestion.

For the name

We will probably go with the following name:

• CountLines()

For the code

• We will probably go to a solution similar to this one: https://stackoverflow.com/a/119572/5619143
• The filter/predicate will probably instead be a Func<string, bool>, so people will be able to apply any kind of predicate

We will try to add it this weekend.

[JonathanMagnan]

Hello @adamfisher ,

The v2.1.1 has been released with this extension methods.

Let me know if everything works as expected.

Best Regards,

Jonathan