# Apply a Function over a List of elements in R Programming – lapply() Function

lapply() function in R Programming Language is used to apply a function over a list of elements.

lapply() function is used with a list and performs the following operations:

lapply(List, length): Returns the length of objects present in the list, List.
lapply(List, sum): Returns the sum of elements held by objects in the list, List.
lapply(List, mean): Returns the mean of elements held by objects in the list, List.
lapply(List, cumsum): Returns the cumulative sum of elements held by objects present inside the list, List.

Syntax: lapply(list, func)

Parameters:

• list: list of elements

## R

 `# R program to illustrate ``# lapply() function ``  ` `# Creating a matrix ``A = ``matrix``(1:9, 3, 3) ``  ` `# Creating another matrix ``B = ``matrix``(10:18, 3, 3)  ``  ` `# Creating a list ``myList = ``list``(A, B) ``  ` `# applying lapply() ``determinant = ``lapply``(myList, det) ``print``(determinant) `

Output:

```[[1]]
[1] 0

[[2]]
[1] 5.329071e-15```

## R

 `# R program to illustrate ``# lapply() function ``  ` `# Creating a matrix ``A = ``matrix``(1:9, 3, 3) ``  ` `# Creating another matrix ``B = ``matrix``(10:18, 3, 3)  ``  ` `# Creating a list ``myList = ``list``(A, B) ``  ` `# applying lapply() ``sum = ``lapply``(myList, sum) ``print``(sum) `

Output:

```     [, 1] [, 2] [, 3]
[1, ]    1    4    7
[2, ]    2    5    8
[3, ]    3    6    9
[1]  28  80 162
[1]   6 120 504```

Previous
Next