title: NAs introduced by coercion WARNING while converting data to numeric from character
body: <p>When I use <code>as.numeric</code> function on <code>chr</code> type data, I get the warning that I mentioned in the title. I tried some recommended ways like <code>x &lt;- gsub(&quot;,&quot;,&quot;&quot;,x)</code> then <code>as.numeric(x)</code> . When I used this way, even I didn't get any warning, I see my variable is still <code>chr</code>  when I used <code>is.numeric(x) </code></p>
  <p>What else can I do? By the way I am trying to work on
  <a href="https://wetransfer.com/downloads/6c8c8061e028e6ed3f526969b56067e120201127191721/433c44" rel="nofollow noreferrer">this data</a> When I used <code>str()</code> function, I saw some variables are <code>chr</code> while some are <code>num</code>. I didn't understand this distinction too.</p>
  <p>Here is my dput of my example data:</p>
  <pre><code>dput(RTG[6:10, 1:5] )
  
  structure(list(Date = c(&quot;02.11.2020&quot;, &quot;02.11.2020&quot;, &quot;02.11.2020&quot;,  &quot;02.11.2020&quot;, &quot;02.11.2020&quot;), Hour = c(&quot;5:00&quot;, &quot;6:00&quot;, &quot;7:00&quot;,  &quot;8:00&quot;, &quot;9:00&quot;), Total..MWh. = c(&quot;25,441.34&quot;, &quot;26,408.77&quot;, &quot;27,850.92&quot;,  &quot;32,157.29&quot;, &quot;34,040.87&quot;), Natural.Gas = c(&quot;7,933.72&quot;, &quot;8,457.68&quot;,  &quot;9,506.90&quot;, &quot;10,778.43&quot;, &quot;11,026.81&quot;), Dammed.Hydro = c(&quot;685.28&quot;,  &quot;1,055.67&quot;, &quot;1,576.70&quot;, &quot;4,423.02&quot;, &quot;6,139.45&quot;)), row.names = 6:10, class = &quot;data.frame&quot;)
  </code></pre>