Difference between 1 and 1 in R Programming

Question

What is the difference between [[1]] and [1] in R? When to use [[ ]] and [ ] in a list?

Answer 1

Hey Latha,

The difference between them is that [[ ]]  is used to access a component in a list or matrix whereas [ ] is used to access a single element in a matrix or array.

Let me explain with an example of the same.

I created a list, matrix to create a new list consisting of a few numbers, list, matrix.

Now ill access elements using [[ ]] and [ ] below.

In the above image list1[[4]] and list1[4] would fetch the same element, but when you want to get a single element of a list part then [ ] is used like above.

A whole matrix can be accessed using [[]] or [] in a whole but to access sub-elements in a list member, we use [ ] such as an element in a matrix within a list as above.