How to convert a list to data frame in R

Question

I am new to R and I'm trying ti convert a list to data frame.

Consider a nested list of data. Length of the list is 145 and each item has a list of length of 30.

Is there any way to convert this structure into a data frame of 145 rows and 30 columns?

l <- replicate(
  145,
  list(sample(letters, 30)),
  simplify = FALSE
)

Answer 1

Let's assume your list of lists is called 'a':

data <- data.frame(matrix(unlist(a), nrow=145, byrow=T))

The above command will convert all character columns to factors. But, to avoid this add the stringsAsFactors parameters to this call.
Refer below:

data <- data.frame(matrix(unlist(a), nrow=145, byrow=T),stringsAsFactors=FALSE)

NOTE: You need to be careful here if all your data is not of same type.
When you pass the data through a matrix, all your data is coerced into a common type.
For Example: If you have one column of character data and one column of numeric data then the numeric data will be coerced to string by matrix() and both to factor by data.frame()