title: Bind rows with different data types
body: <p>I have some dataframes with more than 3000 columns in each, and I want to bind them together.</p>
  
  <p>When I use</p>
  
  <pre><code>library(dplyr)
  
  bind_rows(dataframe1, dataframe2, dataframe3, dataframe4)
  </code></pre>
  
  <p>I get a lot of warnings:</p>
  
  <pre><code>In bind_rows_(x, .id) : Unequal factor levels: coercing to character
  ...
  </code></pre>
  
  <p>I guess it's because a column has data of type factor in one dataframe and data of type character in another dataframe. But how can I solve this problem? </p>
  
  <p>I know I can use</p>
  
  <pre><code>sapply(dataframe1, class)
  </code></pre>
  
  <p>to get the classes of a dataframe, but as there are many columns, it is impossible to go through them all in all 4 dataframes.</p>
  
  <p>This seems to be a problem about the data, but what does it mean that something has type factor? Is it a number?</p>