title: Why does tidyverse show all columns as col_double() when reading data into a tibble?
body: <p>When I read in data to a tidyverse tibble it shows all the columns as <code>col_double()</code>. What does the <code>col_double</code> mean here? </p>
  
  <p><a href="https://i.stack.imgur.com/5UfPu.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5UfPu.png" alt="enter image description here"></a></p>
  
  <p>When I check the tibble using the base R <code>str()</code> function all of the data has been read in as the correct types.<a href="https://i.stack.imgur.com/w0DaB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/w0DaB.png" alt="enter image description here"></a></p>
  
  <p>When I check the type of the tibble it returns list.
  <a href="https://i.stack.imgur.com/lQU2X.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lQU2X.png" alt="enter image description here"></a></p>
  
  <p>This all boils down to three main questions for me:</p>
  
  <ol>
  <li>What is the meaning of <code>col_double</code>?</li>
  <li>Does tidyverse have an alternative to the <code>str()</code> function to check column data types?</li>
  <li>What is the proper way to check if an object is a tibble?</li>
  </ol>