Find list of terms indexed by Lucene

Question

Is it possible to extract the list of all the terms in a Lucene index as a list of strings? I couldn't find that functionality in the doc. Thanks!

Answer 1

In Lucene 4 (and 5):

 Terms terms = SlowCompositeReaderWrapper.wrap(directoryReader).terms("field"); 

Edit:

This seems to be the 'correct' way now (Lucene 6 and up):

LuceneDictionary ld = new LuceneDictionary( indexReader, "field" );
BytesRefIterator iterator = ld.getWordsIterator();
BytesRef byteRef = null;
while ( ( byteRef = iterator.next() ) != null )
{
    String term = byteRef.utf8ToString();
}

Answer 2

Lucene 3:

• C#: C# Lucene get all the index

• Java:

  IndexReader indexReader = IndexReader.open(path); 
  TermEnum termEnum = indexReader.terms(); 
  while (termEnum.next()) { 
      Term term = termEnum.term(); 
      System.out.println(term.text()); 
  }
  termEnum.close(); 
  indexReader.close(); 
  

• Java (all terms for a specific field): How can I get the list of unique terms from a specific field in Lucene?

• Python: Finding a single fields terms with Lucene (PyLucene)