title: How can i convert my column(character) to POSIXct to create time series?
body: <p>I want to convert my <code>PM10</code> <code>dataframe</code> to <code>xts</code> format by using <code>R ;</code> but the type of the first column(<code>date</code>) is character. Therefore, firstly, I need to convert it to <code>POSIXct;</code> but whenever I tried, it runs to NA.</p>
  
  <p>My dates are like this: <code>2014-01-01 00:00</code> </p>
  
  <p>I tried this code and it didn't work. How can I make it work?</p>
  
  <pre><code>date_index  &lt;- as.POSIXct(bes_yillik[,1],tz ="UTC",format = "%Y-%m-%d %H:%M:%S")
  </code></pre>