title: Common column names among data sets in R
body: <p>I have 6 data sets. Their names are: e10_all, e11_all, e12_all, e13_all, e14_all, and e19_all.</p>
  
  <p>All have different numbers of columns and rows, but with some common columns. I need to bind the rows of these columns together. First, I want to determine the columns that are common to all of the data sets. Each of these data sets has around 100 columns, so checking them one-by-one would be very tedious. I've tried a few different methods of comparing two data sets, but with no luck.</p>
  
  <p>I've tried:</p>
  
  <pre><code>library(arsenal)
  summary(compare(e10_all, e11_all))
  
  
  library(lubridate)
  setdiff(e10_all, e11_all)
  
  
  c &lt;- cbind(e10_all[, which(colnames(e10_all)%in% colnames(e11_all))],
             e11_all[, which(colnames(e11_all)%in% colnames(e10_all))])
  
  
  as.data.frame(lapply(intersect(names(e10_all), names(e11_all)), 
                       function(name) e10_all[name] + e11_all[name]))
  </code></pre>
  
  <p>None of these give me what I want. All I need is a list of columns that are common between the two data sets. If possible I would like to compare all 6 data sets.</p>
  
  <p>Thank you</p>