public override DataFrame Read(IDataSourceLocator source, DataFrameSamplingParameters samplingParameters)
{
var textSource = source as TextDataSourceLocator;
if (textSource == null)
{
throw new ArgumentException("Data source should be a text file");
}
var fileName = textSource.FullName;
var headerFlag = textSource.ContainsHeaderWithColumnNames;
var delim = textSource.Delimiter;
var firstK = textSource.NumLinesForTypeInference;
var columnReport = TextIOUtils.CreateColumnReport(fileName, headerFlag, delim, firstK);
var columnCollection = columnReport.ColumnCollection;
var numLines = TextIOUtils.GetNumberOfLines(fileName);
var capacity = samplingParameters.MaxSampleSize;
var ratio = (numLines <= capacity) ? 1.0 : ((double)capacity) / numLines;
var frame = new DataFrame();
frame.Initialize(columnCollection, capacity);
var indices = columnCollection.GetValidIndices();
var length = indices.Length;
var rand = new Random();
using (var stream = new FileStream(fileName, FileMode.Open, FileAccess.Read))
{
using (var reader = new StreamReader(stream))
{
//var colCount = -1;
var line = String.Empty;
if (headerFlag)
{
line = reader.ReadLine();
}
var cnt = 0;
while ((line = reader.ReadLine()) != null)
{
++cnt;
if (rand.NextDouble() > ratio)
{
continue;
}
var parsed = line.Split(delim);
//if (parsed == null || parsed.Length != colCount)
//{
// throw new InvalidOperationException(String.Format("There is a non-conformant record in line {0} of file {1} ", cnt, fileName));
//}
for (int i = 0; i < length; i++)
{
var idx = indices[i];
frame.Add(idx, parsed[idx]);
}
}
}
}
//frame.Cleanup(new List<string>());
return(frame);
}
public override DataFrame Read(IDataSourceLocator source, IList <string> excludedColumnList, DataFrameSamplingParameters samplingParameters)
{
throw new NotImplementedException();
}
public abstract DataFrame Read(IDataSourceLocator source, IList <string> excludedColumnList,
DataFrameSamplingParameters samplingParameters);
public override DataFrame Read(IDataSourceLocator source, DataFrameSamplingParameters samplingParameters)
{
throw new NotImplementedException();
}
public abstract DataFrame Read(IDataSourceLocator source, DataFrameSamplingParameters samplingParameters);
