title: assertr: Automatically verify assumptions on columns
body: <p>I want to automatically verify assumptions on columns of my tibble using <a href="https://cran.r-project.org/web/packages/assertr/vignettes/assertr.html" rel="nofollow noreferrer">assertr</a>. The problem is that I have hundreds of columns so I can't apply them column by column. Data looks like this: </p>
  
  <pre><code>df &lt;- tibble(
    x = c(1,0,1,1,2), 
    y = c('A', 'B', 'C', 'D', 'A'), 
    z = c(1/3, 4, 5/7, 100, 3))
  </code></pre>
  
  <p>Then I have another tibble which describes types of columns: </p>
  
  <pre><code>df_map &lt;- tibble(
    col = c('x','y','z'), 
    col_type = c('POSSIBLE VALUES 0 AND 1', 'LESS THAN 1 MISSING VALUE', 'POSITIVE VALUE')
  )
  </code></pre>
  
  <p>This can be written like:  </p>
  
  <pre><code>df %&gt;%  
    assert(in_set(0,1), x) %&gt;%
    assert_rows(num_row_NAs, within_bounds(0,1), y) %&gt;%
    verify(z &gt; 0)
  </code></pre>
  
  <p>My question is how to apply these verifications (or any other) with this mapping so I don't need to write them for every single column. </p>