Converting nested list (unequal length) to data frame

dataframe, r

Solution

We get the `length` of `list` element ('indx') by looping with `sapply`. In the recent version of `R`, we can use `lengths` to replace the `sapply(.., length)` step. We change the `length` of each element to the `max` length from the 'indx' (`length<-`) and thereby pad `NA` values at the end of the `list` elements with length less than the `max` length. We can `rbind` the `list` elements, convert to `data.frame` and change the column names.

 indx <- sapply(lst, length)
 #indx <- lengths(lst) 
 res <- as.data.frame(do.call(rbind,lapply(lst, `length<-`,
                          max(indx))))

 colnames(res) <- names(lst[[which.max(indx)]])
 res
 # sk ques pval diff  imp
 #1 10 sfsf 0.05 <NA> <NA>
 #2 24 wwww 0.11  0.3 <NA>
 #3 24 wwww 0.11  0.3    2

data

 lst <- list(structure(c("10", "sfsf", "0.05"), .Names = c("sk", "ques", 
 "pval")), structure(c("24", "wwww", "0.11", "0.3"), .Names = c("sk", 
 "ques", "pval", "diff")), structure(c("24", "wwww", "0.11", "0.3", 
 "2"), .Names = c("sk", "ques", "pval", "diff", "imp")))

Problem

Original source

Related problems

• Combine some csv files into one - different number of columns
• Combine some csv files into one - different number of columns