Separating a List into Columns-CodePudding

I have this list in R:

my_list = list("word",c("word", "word"), "word", c("word", "word","word"), "word")

[[1]]
[1] "word"

[[2]]
[1] "word" "word"

[[3]]
[1] "word"

[[4]]
[1] "word" "word" "word"

[[5]]
[1] "word"

I would like to convert this list into a data frame that looks something like this:

  col1 col2 col3
1 word          
2 word word     
3 word          
4 word word word
5 word   

# source code of the desired output

structure(list(col1 = c("word", "word", "word", "word", "word"
), col2 = c("", "word", "", "word", ""), col3 = c("", "", "", 
"word", "")), class = "data.frame", row.names = c(NA, -5L))

I tried to use the answer provided here (How to split a column of list into several columns using R) for my question:

z = my_list
x <- do.call(rbind, z)
colnames(x) <- LETTERS[1:ncol(x)]
h = data.frame(cbind(z[c("sg", "time")], x))

But this is not giving me the desired output.

Can someone please show me how to do this?

Thank you!

CodePudding user response：

You could use lapply to make the list element lengths the same, then do.call with rbind to create the desired output:

do.call(rbind, lapply(my_list, `length<-`, max(lengths(my_list))))

Output

#      [,1]   [,2]   [,3]  
# [1,] "word" NA     NA    
# [2,] "word" "word" NA    
# [3,] "word" NA     NA    
# [4,] "word" "word" "word"
# [5,] "word" NA     NA

If you wanted there to be blanks as opposed to NA values:

new_df <- do.call(rbind, lapply(my_list, `length<-`, max(lengths(my_list))))
new_df[is.na(new_df)] <- ""

Output:

#      [,1]   [,2]   [,3]  
# [1,] "word" ""     ""    
# [2,] "word" "word" ""    
# [3,] "word" ""     ""    
# [4,] "word" "word" "word"
# [5,] "word" ""     ""

CodePudding user response：

With stringi::stri_list2matrix:

library(stringi)
data.frame(stri_list2matrix(my_list, byrow = TRUE))
#     X1   X2   X3
# 1 word <NA> <NA>
# 2 word word <NA>
# 3 word <NA> <NA>
# 4 word word word
# 5 word <NA> <NA>

Or with sapply:

t(sapply(my_list, "length<-", max(lengths(my_list))))