title: R strsplit() with multiple criteria
body: <p>I am trying to split sentences based on different criteria. I am looking to split some sentences after " is" and some after " never". I was able to split sentences based on either of these conditions but not both.</p>
  
  <pre><code>str &lt;- matrix(c("This is line one", "This is not line one", 
                  "This can never be line one"), nrow = 3, ncol = 1)
  
  &gt;str
       [,1]                        
  [1,] "This is line one"          
  [2,] "This is not line one"      
  [3,] "This can never be line one"
  
  str2 &lt;- apply(str, 1, function (x) strsplit(x, " is", fixed = TRUE))
  
  &gt; str2
  [[1]]
  [[1]][[1]]
  [1] "This"      " line one"
  
  
  [[2]]
  [[2]][[1]]
  [1] "This"          " not line one"
  
  
  [[3]]
  [[3]][[1]]
  [1] "This can never be line one"
  </code></pre>
  
  <p>I would like to split the last sentence after " never". I am not sure how to do that.</p>