title: how can i denormalization the data of a dataframe
body: <p>I have tried following one for normalization of a dataframe. I have problem in      denormalising dataframe. 
   how to denormalize it.</p>
  
  <pre><code>      form &lt;- function(x) {(x - min(x, na.rm=TRUE))/(max(x,na.rm=TRUE) - 
                                               min(x, na.rm=TRUE))} 
        normed &lt;- as.data.frame(lapply(m1, form)) 
  </code></pre>
  
  <p>dataset</p>
  
  <pre><code>      'data.frame': 96611 obs. of  10 variables:
         $ Timestamp       : num  1388619000 1388619900 1388620800 1388621700    1388622600 ...
         $ avg.price       : num  -14.55 -10.73 0.65 0.62 0.18 ...
         $ weekday         : num  4 4 5 5 5 5 5 5 5 5 ...
         $ total.energy    : num  0.76 0.18 330.56 1.75 1.62 ...
         $ O.avgprice      : num  -10.17 -13.79 -2.64 -9.77 -2.96 ...
         $ O.firstquartil  : num  -20 -24.25 -5.42 -13.74 -4.45 ...
         $ O.thirdquartil  : num  -3.29 -6.78 -1.3 -0.19 -2.2 0 5 -1.92 0.22 5.08 ...
  </code></pre>