title: Combine two lists of dataframes, dataframe by dataframe
body: <p>I have what is no doubt a simple problem. I have spent the last hour or so looking around for a solution but am clearly missing something. If this is indeed a duplicate please link me to the right way to do this:</p>
  
  <p>Example data:</p>
  
  <pre><code>names &lt;- c("Cycling1.opr", "Cycling2.opr", "Cycling3.opr")
  mydf1 &lt;- data.frame(V1=c(1:5), V2=c(21:25)) 
  mydf2 &lt;- data.frame(V1=c(1:10), V2=c(21:30))
  mydf3 &lt;- data.frame(V1=c(1:30), V2=c(21:50))
  opr &lt;- list(mydf1,mydf2,mydf3)
  mydf4 &lt;- data.frame(timestamp=c(1:5))
  mydf5 &lt;- data.frame(timestamp=c(1:10))
  mydf6 &lt;- data.frame(timestamp=c(1:30))
  timestamp &lt;- list(mydf4,mydf5,mydf6)
  names(opr) &lt;- names
  names(timestamp) &lt;- names
  </code></pre>
  
  <p>Each list (opr and timestamp) always has the same number of data.frames and when having the same name, each of these data.frames is always the same length. What I would like to do is merge each similarly named dataframe into a single dataframe as part of a final list (perhaps named finalopr) such that its structure is as follows. </p>
  
  <pre><code>dput(finalopr)
  list(structure(list(V1 = 1:5, V2 = 21:25, timestamp = 1:5), .Names = c("V1", 
  "V2", "timestamp"), row.names = c(NA, -5L), class = "data.frame"), 
  structure(list(V1 = 1:10, V2 = 21:30, timestamp = 1:10), .Names = c("V1", 
  "V2", "timestamp"), row.names = c(NA, -10L), class = "data.frame"), 
  structure(list(V1 = 1:30, V2 = 21:50, timestamp = 1:30), .Names = c("V1", 
  "V2", "timestamp"), row.names = c(NA, -30L), class = "data.frame"))
  </code></pre>