title: Changing values when converting column type to numeric
body: <p>I have a data file with the format from above.<br>
  I loaded it into R, and tried to plot a histogram with the values from the dist column and I have got the error "x must be numeric".Therefore I tried to change the format.</p>
  
  <pre><code>&gt; head(data)
  
      V1        V2
  1 type gene_dist
  2    A     64667
  3    A     76486
  4    A     97416
  5    A     30876
  6    A     88018
  
  &gt; summary(data)
      V1            V2     
   A   : 67   100    :  1  
   B   :122   100906 :  1  
   type:  1   102349 :  1  
              1033   :  1  
              10544  :  1  
              10745  :  1  
              (Other):184  
  </code></pre>
  
  <p>I tried to set the format for the column using <code>sapply</code> but the values are changed:</p>
  
  <pre><code>&gt; data[,2]&lt;-sapply(data[,2],as.numeric)
  
  &gt; head(data)
      V1  V2
  1 type 190
  2    A 146
  3    A 166
  4    A 189
  
  summary(data)
      V1            V2        
   A   : 67   Min.   :  1.00  
   B   :122   1st Qu.: 48.25  
   type:  1   Median : 95.50  
              Mean   : 95.50  
              3rd Qu.:142.75  
              Max.   :190.00 
  </code></pre>
  
  <p>Does anyone know why is this happening?</p>