public static TX Lower(TX a)
{
if (a.IsEmpty)
{
return(a);
}
var sb = new StringBuilder();
ReadOnlyMemoryUtils.AddLowerCaseToStringBuilder(a.Span, sb);
return(sb.ToString().AsMemory());
}
protected override Delegate GetGetterCore(IChannel ch, IRow input, int iinfo, out Action disposer)
{
Host.AssertValueOrNull(ch);
Host.AssertValue(input);
Host.Assert(0 <= iinfo && iinfo < Infos.Length);
Host.Assert(Infos[iinfo].TypeSrc.IsVector & Infos[iinfo].TypeSrc.ItemType.IsText);
disposer = null;
var ex = _exes[iinfo];
Language stopWordslang = ex.Lang;
var lang = default(ReadOnlyMemory <char>);
var getLang = ex.LangsColIndex >= 0 ? input.GetGetter <ReadOnlyMemory <char> >(ex.LangsColIndex) : null;
var getSrc = GetSrcGetter <VBuffer <ReadOnlyMemory <char> > >(input, iinfo);
var src = default(VBuffer <ReadOnlyMemory <char> >);
var buffer = new StringBuilder();
var list = new List <ReadOnlyMemory <char> >();
ValueGetter <VBuffer <ReadOnlyMemory <char> > > del =
(ref VBuffer <ReadOnlyMemory <char> > dst) =>
{
var langToUse = stopWordslang;
UpdateLanguage(ref langToUse, getLang, ref lang);
getSrc(ref src);
list.Clear();
var srcValues = src.GetValues();
for (int i = 0; i < srcValues.Length; i++)
{
if (srcValues[i].IsEmpty)
{
continue;
}
buffer.Clear();
ReadOnlyMemoryUtils.AddLowerCaseToStringBuilder(srcValues[i].Span, buffer);
// REVIEW nihejazi: Consider using a trie for string matching (Aho-Corasick, etc.)
if (StopWords[(int)langToUse].Get(buffer) == null)
{
list.Add(srcValues[i]);
}
}
VBufferUtils.Copy(list, ref dst, list.Count);
};
return(del);
}
private void LoadStopWords(IHostEnvironment env, IChannel ch, ArgumentsBase loaderArgs, out NormStr.Pool stopWordsMap)
{
Contracts.AssertValue(env);
env.AssertValue(ch);
ch.AssertValue(loaderArgs);
if ((!string.IsNullOrEmpty(loaderArgs.Stopwords) || Utils.Size(loaderArgs.Stopword) > 0) &&
(!string.IsNullOrWhiteSpace(loaderArgs.DataFile) || loaderArgs.Loader != null ||
!string.IsNullOrWhiteSpace(loaderArgs.StopwordsColumn)))
{
ch.Warning("Explicit stopwords list specified. Data file arguments will be ignored");
}
var src = default(ReadOnlyMemory <char>);
stopWordsMap = new NormStr.Pool();
var buffer = new StringBuilder();
var stopwords = loaderArgs.Stopwords.AsMemory();
stopwords = ReadOnlyMemoryUtils.TrimSpaces(stopwords);
if (!stopwords.IsEmpty)
{
bool warnEmpty = true;
for (bool more = true; more;)
{
ReadOnlyMemory <char> stopword;
more = ReadOnlyMemoryUtils.SplitOne(stopwords, ',', out stopword, out stopwords);
stopword = ReadOnlyMemoryUtils.TrimSpaces(stopword);
if (!stopword.IsEmpty)
{
buffer.Clear();
ReadOnlyMemoryUtils.AddLowerCaseToStringBuilder(stopword.Span, buffer);
stopWordsMap.Add(buffer);
}
else if (warnEmpty)
{
ch.Warning("Empty strings ignored in 'stopwords' specification");
warnEmpty = false;
}
}
ch.CheckUserArg(stopWordsMap.Count > 0, nameof(Arguments.Stopwords), "stopwords is empty");
}
else if (Utils.Size(loaderArgs.Stopword) > 0)
{
bool warnEmpty = true;
foreach (string word in loaderArgs.Stopword)
{
var stopword = word.AsSpan();
stopword = stopword.Trim(' ');
if (!stopword.IsEmpty)
{
buffer.Clear();
ReadOnlyMemoryUtils.AddLowerCaseToStringBuilder(stopword, buffer);
stopWordsMap.Add(buffer);
}
else if (warnEmpty)
{
ch.Warning("Empty strings ignored in 'stopword' specification");
warnEmpty = false;
}
}
}
else
{
string srcCol = loaderArgs.StopwordsColumn;
var loader = LoadStopwords(env, ch, loaderArgs.DataFile, loaderArgs.Loader, ref srcCol);
int colSrc;
if (!loader.Schema.TryGetColumnIndex(srcCol, out colSrc))
{
throw ch.ExceptUserArg(nameof(Arguments.StopwordsColumn), "Unknown column '{0}'", srcCol);
}
var typeSrc = loader.Schema[colSrc].Type;
ch.CheckUserArg(typeSrc.IsText, nameof(Arguments.StopwordsColumn), "Must be a scalar text column");
// Accumulate the stopwords.
using (var cursor = loader.GetRowCursor(col => col == colSrc))
{
bool warnEmpty = true;
var getter = cursor.GetGetter <ReadOnlyMemory <char> >(colSrc);
while (cursor.MoveNext())
{
getter(ref src);
if (!src.IsEmpty)
{
buffer.Clear();
ReadOnlyMemoryUtils.AddLowerCaseToStringBuilder(src.Span, buffer);
stopWordsMap.Add(buffer);
}
else if (warnEmpty)
{
ch.Warning("Empty rows ignored in data file");
warnEmpty = false;
}
}
}
ch.CheckUserArg(stopWordsMap.Count > 0, nameof(Arguments.DataFile), "dataFile is empty");
}
}