title: Julia: How to obtain the types of every column of a DataFrame/Table?
body: <p>There must be an easy way to obtain the column types of every column of a DataFrame. Currently, I do</p>
  
  <pre><code>using DataFrames
  a = DataFrame(a = [1,2,3], str = ["a","b","c"], f = [0.0, 1.0, 5.0])
  [eltype(Array(col)) for col in eachcol(a)]
  </code></pre>
  
  <p>Is the best way? Appreciate more efficient and elegant solutions</p>