r - Convert a list to a data frame

I have a nested list of data. Its length is 132 and each item is a list of length 20. Is there a quick way to convert this structure into a data frame that has 132 rows and 20 columns of data?

Here is some sample data to work with:

l <- replicate(
  132,
  list(sample(letters, 20)),
  simplify = FALSE
)

Answer

Assuming your list of lists is called l:

df <- data.frame(matrix(unlist(l), nrow=length(l), byrow=T))

The above will convert all character columns to factors, to avoid this you can add a parameter to the data.frame() call:

df <- data.frame(matrix(unlist(l), nrow=132, byrow=T),stringsAsFactors=FALSE)