title: Gather or pivot_longer on multiple columns?
body: <p>This is the data that I have:</p>
  <pre><code>id&lt;-c(1:7)
  emp1&lt;-c('ft','ft','pt','pt','ft','no','no')
  emp2&lt;-c('ft','ft','ft','ft','no','pt','ft')
  marstat1&lt;-c('married','married','divorced','single','single','single','single')
  marstat2&lt;-c('divorced','married','divorced','single','single','married','single')
  df&lt;-data.frame(id,emp1,emp2,marstat1,marstat2) 
  </code></pre>
  <p>I want to reshape (from wide to long) it into</p>
  <pre><code>id&lt;-c(1,1,2,2,3,3,4,4,5,5,6,6,7,7)
  year&lt;-c(rep(1:2,7))
  emp&lt;-c('ft','ft','ft','ft','pt','ft','pt','ft','ft','no','no','pt','no','ft')
  marstat&lt;-c('married','divorced','married','married','divorced','divorced','single','single','single','single','single','married','single','single')
  df2&lt;-data.frame(id,year,emp,marstat)
  </code></pre>
  <p>I tried to use dplyr::gather, but it gives me 4 rows each id instead of 2. And it's not clear to me what to do with the year dimension (I don't need two columns of year, just one)</p>
  <pre><code>df2&lt;-df %&gt;% 
    gather(key='year',value='emp',emp1,emp2) %&gt;% 
    gather(key='year2',value='marstat',marstat1,marstat2)
  </code></pre>