title: Convert "(3e+04,3.5e+04]" type to number in r
body: <p>I have data set of car speed on a road, and the distance of the car from the start point of measuring.</p>
  
  <p>I wanted to check what is the mean and se in each 5 KM down the road, so I sorted the data by 'DistanceFromStart' and made a table using a function I build:</p>
  
  <pre><code>speedByKM &lt;- function(testFile){
       setDT(a1a2011)[, list(Speed=mean(Speed)), by=list(cut(DistanceFromStart,breaks= seq(0, max(DistanceFromStart)+5000, by = 5000),include.lowest=TRUE))]-&gt;res
      setDT(a1a2011)[, list(Speed=se(Speed)), by=list(cut(DistanceFromStart,breaks= seq(0, max(DistanceFromStart)+5000, by = 5000),include.lowest=TRUE))]-&gt;res1
      res$se = res1$Speed 
         return(res)
   }
  </code></pre>
  
  <p>The table I got is:</p>
  
  <pre><code>            cut    Speed         se
  1: (3e+04,3.5e+04] 88.16993 0.04784163
  
  2:   (5e+03,1e+04] 94.33507 0.02121293
  
  3: (2e+04,2.5e+04] 99.26032 0.03680951
  
  4: (2.5e+04,3e+04] 90.31163 0.03991980
  
  5:       [0,5e+03] 94.69139 0.01872111
  
  6: (1e+04,1.5e+04] 94.70515 0.02661366
  
  7: (1.5e+04,2e+04] 97.34650 0.02880336
  </code></pre>
  
  <p>How can I make the KM show as a number?
  for example, instead of '5e+03' to show 5000? 
  Thank you.</p>