title: Query using geom_bar() of ggplot2 - R
body: <p>I have a similar data frame as follows:</p>
  
  <pre><code>mapDF &lt;- structure(list(var = c(11L, 3L, 4L, 15L, 19L, 17L, 1L), approvals = c(10.5233545765422, 
  67.9809421770218, 9.66394835013545, 2.93736399165075, 3.36787205222721, 
  4.0168261757783, 1.50969267664431)), .Names = c("var", "approvals"
  ), row.names = c(NA, -7L), class = "data.frame")
  </code></pre>
  
  <p>When I try creating a bar graph using the data frame above using:</p>
  
  <pre><code>gplot &lt;- ggplot(mapDF, aes(x= mapDF[1], y= mapDF[2])) + geom_bar()
  </code></pre>
  
  <p>.. I get the following messages with <strong>nothing</strong> showing up in the 'Plots' section of RStudio:</p>
  
  <pre><code>Don't know how to automatically pick scale for object of type data.frame. Defaulting to continuous
  Don't know how to automatically pick scale for object of type data.frame. Defaulting to continuous
  Error: stat_bin requires the following missing aesthetics: x
  </code></pre>
  
  <p>Can anyone please point out my error?</p>