The list() is a function used to construct, coerce, and check for both kinds of R lists. All lists within R are Generic Vectors. The list() function returns a list of dotted pair lists composed of its arguments with each value either tagged or untagged, depending on how the argument was specified.
as.list() in R
The as.list() is a built-in R function that converts objects to lists. The as.list() function is used to convert an object to a list. These objects can be Vectors, Matrices, Factors, and data frames.
Syntax
as.list(object)
Parameters
The as.list() function takes an object as a parameter, a vector, matrix, factor, or data frame.
Example
Passing a vector as a parameter to the as.list() function.
rv <- 1:5
rv
cat("After converting a vector to list", "\n")
rl <- as.list(rv)
rl
Output
[1] 1 2 3 4 5
After converting a vector to list
[[1]]
[1] 1
[[2]]
[1] 2
[[3]]
[1] 3
[[4]]
[1] 4
[[5]]
[1] 5
This is the conversion of vector to list.
Converting data frame to list using as.list() function
R provides a built-in data set that we can use to create a data frame and then use the as.list() function to convert the data frame into the list.
data("ToothGrowth")
df <- head(ToothGrowth)
df
cat("After converting a data frame to list", "\n")
rl <- as.list(df)
rl
Output
len supp dose
1 4.2 VC 0.5
2 11.5 VC 0.5
3 7.3 VC 0.5
4 5.8 VC 0.5
5 6.4 VC 0.5
6 10.0 VC 0.5
After converting a data frame to list
$len
[1] 4.2 11.5 7.3 5.8 6.4 10.0
$supp
[1] VC VC VC VC VC VC
Levels: OJ VC
$dose
[1] 0.5 0.5 0.5 0.5 0.5 0.5
Converting matrix to list using as.list() function
To convert a matrix to list, use the as.list() function.
vt <- c("Millie", "Noah", "Finn", "Sadie")
mtrx <- matrix(vt, nrow = 2, ncol = 2)
mtrx
cat("After converting a matrix to list", "\n")
rl <- as.list(mtrx)
rl
Output
[,1] [,2]
[1,] "Millie" "Finn"
[2,] "Noah" "Sadie"
After converting a matrix to list
[[1]]
[1] "Millie"
[[2]]
[1] "Noah"
[[3]]
[1] "Finn"
[[4]]
[1] "Sadie"
Converting a factor to list using as.list() function
To create a factor in R, use the factor() method. To convert a factor to a list, use the as.list() function.
rv <- c("Millie", "Noah")
rf <- factor(rv)
rf
cat("After converting a factor to list", "\n")
rl <- as.list(rf)
rl
Output
[1] Millie Noah
Levels: Millie Noah
After converting a factor to list
[[1]]
[1] Millie
Levels: Millie Noah
[[2]]
[1] Noah
Levels: Millie Noah
That is it for this tutorial.
See also

Krunal Lathiya is an Information Technology Engineer by education and web developer by profession. He has worked with many back-end platforms, including Node.js, PHP, and Python. In addition, Krunal has excellent knowledge of Data Science and Machine Learning, and he is an expert in R Language. Krunal has written many programming blogs, which showcases his vast expertise in this field.