How to Convert a List to a dataframe in R

List data structure in R is a useful structure store different data types. In this tutorial, we will learn how to convert a list into a dataframe. Here we will assume that the list has multiple vectors of same size.

Creating a list with vectors of equal sizes

Let us get started by create an example list with two variables of equal length.

list_of_equalsize <- list(id = letters[1:3],
                       col1 = 1:3)

Our list looks like this, we have one character variable and one numerical variable.

list_of_equalsize

## $id
## [1] "a" "b" "c"
## 
## $col1
## [1] 1 2 3

List to Dataframe with as.data.frame()

One of the ways to convert a list of equal size to a dataframe is to use as.data.frame() available in base R.

as.data.frame(list_of_equalsize)

##   id col1
## 1  a    1
## 2  b    2
## 3  c    3

library(tidyverse)

List to Dataframe with as_tibble()

Another way we can convert a list into a dataframe is to use tidyverse’s as_tibble() function. as_tibble function converts the list into a tibble which is a dataframe like structure available in tidyverse.

as_tibble(list_of_equalsize)

## # A tibble: 3 x 2
##   id     col1
##   <chr> <int>
## 1 a         1
## 2 b         2
## 3 c         3

Note that the examples above can convert when the list have vectors of same size and will not work if they differ in lengths. To illustrate that let us make a list with unequal size vectors.

as.tibble(list_of_equalsize)
list_of_unequals <- list(id = letters[1:4],
                       col1 = 1:3)
list_of_unequals

list_of_unequals <- list(id = letters[1:4],
                       col1 = 1:3)

list_of_unequals
## $id
## [1] "a" "b" "c" "d"
## 
## $col1
## [1] 1 2 3

If we try to convert the list with unequal vector size, we would get the following error.

as.data.frame(list_of_unequals)

Error in (function (..., row.names = NULL, check.rows = FALSE, check.names = TRUE, : arguments imply differing number of rows: 4, 3