Converting nested list to dataframe

Question

The goal is to convert a nested list which sometimes contain missing records into a data frame. An example of the structure when there are missing records is:

str(mylist)  List of 3  $ :List of 7   ..$ Hit    : chr "True"   ..$ Project: chr "Blue"   ..$ Year   : chr "2011"   ..$ Rating : chr "4"   ..$ Launch : chr "26 Jan 2012"   ..$ ID     : chr "19"   ..$ Dept   : chr "1, 2, 4"  $ :List of 2   ..$ Hit  : chr "False"   ..$ Error: chr "Record not found"  $ :List of 7   ..$ Hit    : chr "True"   ..$ Project: chr "Green"   ..$ Year   : chr "2004"   ..$ Rating : chr "8"   ..$ Launch : chr "29 Feb 2004"   ..$ ID     : chr "183"   ..$ Dept   : chr "6, 8" 

When there are no missing records the list can be converted into a data frame using data.frame(do.call(rbind.data.frame, mylist)). However, when records are missing this results in a column mismatch. I know there are functions to merge data frames of non-matching columns but I'm yet to find one that can be applied to lists. The ideal outcome would keep record 2 with NA for all variables. Hoping for some help.

Edit to add dput(mylist):

list(structure(list(Hit = "True", Project = "Blue", Year = "2011",  Rating = "4", Launch = "26 Jan 2012", ID = "19", Dept = "1, 2, 4"), .Names = c("Hit",  "Project", "Year", "Rating", "Launch", "ID", "Dept")), structure(list( Hit = "False", Error = "Record not found"), .Names = c("Hit",  "Error")), structure(list(Hit = "True", Project = "Green", Year = "2004",  Rating = "8", Launch = "29 Feb 2004", ID = "183", Dept = "6, 8"), .Names = c("Hit",  "Project", "Year", "Rating", "Launch", "ID", "Dept"))) 

Answer 1

You can also use (at least v1.9.3) of rbindlist in the data.table package:

library(data.table)  rbindlist(mylist, fill=TRUE)  ##      Hit Project Year Rating      Launch  ID    Dept            Error ## 1:  True    Blue 2011      4 26 Jan 2012  19 1, 2, 4               NA ## 2: False      NA   NA     NA          NA  NA      NA Record not found ## 3:  True   Green 2004      8 29 Feb 2004 183    6, 8               NA