title: R reads %d%b%Y date's month in wrong language
body: <p>I am running a code my colleague has written on his Rstudio some time ago and I am stuck on what appears to be a very silly problem. I have a variable in a dataframe that is a character and represents a date, such as</p>
  
  <pre><code>30jan2016
  38feb2016
  </code></pre>
  
  <p>I need to transform this character string into a date variable and I am using the following:</p>
  
  <pre><code>df$newvar &lt;- format(as.Date(df$oldvar, format="%d%b%Y"), format="%Y%m%d")
  </code></pre>
  
  <p>This is what I get:</p>
  
  <pre><code>NA
  2016-02-28
  </code></pre>
  
  <p>After some though I realised that my Rstudio is reading the "month" part of the string in Italian (below you can find the comparison of month abbreviations ENG-ITA), and is correctly decoding only what it can read in ITALIAN. Changing global language options didn't help (and anyway R language was already set to English). Any ideas?</p>
  
  <p>Thanks!</p>
  
  <pre><code>ENG    ITA
  jan    gen
  feb    feb
  mar    mar
  apr    apr
  may    mag
  jun    giu
  jul    lug
  aug    ago
  sep    set
  oct    ott
  nov    nov
  dec    dic
  </code></pre>
  
  <p>NOTE: Of course I could replace parts of the string and then run the piece of code, but I need this code to run on ANY computer, in English.</p>