/// <summary>
/// Return an in-memory table that contains the topN rows from the table in the filename.
/// </summary>
/// <param name="builder">ignored</param>
/// <param name="filename">filename of table to load. Schema is inferred from header row.</param>
/// <param name="topN">reads the topN rows from the table.</param>
/// <returns>a in-memory table containing the topN rows from the supplied file.</returns>
public static MutableDataTable ReadSampleTopN(this DataTableBuilder builder, string filename, int topN = 100)
{
Debug.Assert(builder != null);
if (filename == null)
{
throw new ArgumentNullException("filename");
}
DataTable source = new StreamingDataTable(filename);
MutableDataTable dt = Analyze.SampleTopN(source, topN);
return(dt);
}
public static MutableDataTable Read(TextReader stream, char delimiter = '\0', string[] defaultColumns = null)
{
// TextReader is not seekable. Need to convert to a Stream so we can seek.
// We're asking for a Mutable dt anyways, so it's already expected to load it in memory.
string contents = stream.ReadToEnd();
var bytes = Encoding.UTF8.GetBytes(contents);
contents = null;
using (MemoryStream ms = new MemoryStream(bytes))
{
var dtLazy = new StreamingDataTable(ms, defaultColumns, delimiter);
var dt = Utility.ToMutable(dtLazy);
return(dt);
}
}
public static MutableDataTable Read(TextReader stream, char delimiter = '\0', string[] defaultColumns = null)
{
// TextReader is not seekable. Need to convert to a Stream so we can seek.
// We're asking for a Mutable dt anyways, so it's already expected to load it in memory.
string contents = stream.ReadToEnd();
var bytes = Encoding.UTF8.GetBytes(contents);
contents = null;
using (MemoryStream ms = new MemoryStream(bytes))
{
var dtLazy = new StreamingDataTable(ms, defaultColumns, delimiter);
var dt = Utility.ToMutable(dtLazy);
return dt;
}
}
