title: Replace a single column values
body: <p>How do i replace values from a single column of a dataframe. For example all 0 values in column dataz to values of 1</p>
  
  <pre><code>     datay dataz
   [1,]     0   100
   [2,]     2   101
   [3,]     3   102
   [4,]     4   103
   [5,]    10     0
   [6,]    11     0
   [7,]     0     0
   [8,]     0     0
   [9,]     0     0
  [10,]    12    11
  [11,]    45    12
  </code></pre>