title: Creating a heatmap using .csv in R
body: <p>I'm trying to figure out how to create heatmaps.</p>
  
  <p>I have a csv file that I've imported with 61 observations of 58 variables, formatted as follows and have changed all na values to 0s. </p>
  
  <pre class="lang-none prettyprint-override"><code>      T1   T2   T3   T4
  1 aaa 3    6    3    0
  2 aab 1    8    5    0
  3 abb 2    5    0    0
  4 bbb 10   0    10   7
  5 bbc 8    2    8    1
  
  heat &lt;- data.frame(read.csv("heatdata.csv", header=T))
  write.csv(heat,"heat.csv",na="0")
  heat &lt;- data.frame(read.csv("heat.csv", header=T))
  </code></pre>
  
  <p>I would like to create heatmaps, both using all of the data in the data frame, as well as specifying particular columns (only T2 and T3, for example). I have tried using both heatmap and heatmap.2 but I obviously don't have my data formatted correctly and am not sure how to handle the data.</p>
  
  <pre><code>heatmap(heat2)
  Error in heatmap(heat2) : 'x' must be a numeric matrix
  </code></pre>