title: Read in specific, pattern-matched rows from a file
body: <p>I have a file that is tab-delimited and contains multiple tables each headed by a title, for example "Azuay\n", "Bolivar\n", "Cotopaxi\n", etc, and each table separated by two newlines. Within R, how can I read in this file and select only the table (i.e. specified rows) corresponding to e.g. "Bolivar", while ignoring the table beneath corresponding to "Cotopaxi" and the table above corresponding to "Azuay". </p>
  
  <p>NB. I'd prefer not to modify the table outside R.</p>
  
  <p>The data looks like this. The file is tab-separated.</p>
  
  <pre><code> Azuay
   region begin       stop
   1A     2017761     148749885
   1A     148863885   150111299
   1A     150329391   150346152
   1A     150432847   247191037
  
  
   Bolivar
   region begin           stop 
   2A     2785            242068364
   2A     736640          198339289
  
  
   Cotopaxi
   region begin           stop 
   4A     2282            9951846
   4A     11672561        11906166
  </code></pre>