The difference between bracket [ ] and double bracket [[ ]] for accessing the elements of a list or dataframe

Question

There are two different methods for accessing the element of a list or data frame- [ ] and [[ ]] , what is the difference between them?

When should I use one over the other and what’s the difference between them?

Answer 1

The main difference between these two are, mainly Double brackets accesses a list element whereas a single element gives back a list with a single element.

E.x.

lst <- list('one','two','three')

q <- lst[1]

class(q)

## returns "list"

q <- lst[[1]]

class(q)

## returns "character"

Hope this helps.