R TM ngrams showing in most frequent terms but cannot be accessed
<p>Working with R{tm}, my problem is that a term shows up in most frequent terms. When i try to inspect an intersect of the dtm with the particular term, i get a blank. MWE here. After regular tm_map transforms, I have a proper <code>DocumentTermMatrix</code>. I call terms with frequency more than 10, like so: </p>

<pre><code>&gt; findFreqTerms(dtm4, lowfreq=10)
 [1] "bank america"      "cent stake"        "deutsche bank"    
 [4] "fibre network"     "auto industry"     "interest rates"   
 [7] "optical fibre"     "points cent"       "post offices"     
[10] "postal department" "alibaba investment"         
&gt;
</code></pre>

<p>I want to find out which all documents contain "auto industry"? I run an intersect, like so: </p>

<pre><code>&gt; inspect(dtm4[1:10, intersect(dtm4,"auto industry")]).
</code></pre>

<p>I get zero entries. </p>

<pre><code>`&lt;&lt;DocumentTermMatrix (documents: 10, terms: 0)&gt;&gt;
Non-/sparse entries: 0/0
Sparsity           : 100%
Maximal term length: 0
Weighting          : term frequency (tf)`
</code></pre>

<p>The intersect operation works perfectly for unigrams; but this problem sems to be while passing <code>RWeka::ngrams</code> to the <code>dtm</code>. Is there something wrong that I am doing, or does the 'findFreqTerms()` create a special (virtual?) view, which cannot be accessed by intersect?
Many thanks.</p>