title: Merge Dataframes by index of a dataframe
body: <pre><code>library(dplyr)
  library(jsonlite)
  test &lt;- 'https://api.data.gov.sg/v1/transport/carpark-availability'
  data &lt;- fromJSON(test)
  a &lt;- as.data.frame(data$items$carpark_data)
  b &lt;- a[[1]]
  c &lt;- bind_rows(b, .id = "carpark_info")
  </code></pre>
  
  <p>Upon inspection, I noticed a has 2047 rows and c has 2214 rows. </p>
  
  <p>For instance, a in row 107 (1 observation) has 3 corresponding values (observations) in c</p>
  
  <p>How can I full_join them so a will have the same number of rows as c?</p>