Is it true that this is a vector?

c(1)

Yes,

because `c(1)` is a collection of integer values of length one.

Is it true that this is a vector?

c(1,2,3)

Yes,

because `c(1,2,3)` is a collection of integer values of length three.

Is it true that this is a vector?

c("cat","dog","mouse")

Yes,

because `c("cat","dog","mouse")` is a collection of character values.

Is it true that this is a vector?

c(2.3,4.1)

Yes,

because `c(2.3,4.1)` is a collection of double values.

Is it true that this is a vector?

c(TRUE,TRUE,FALSE)

Yes,

because `c(TRUE,TRUE,FALSE)` is a collection of logical values.

Is it true that this is a vector?

list(1,"cat",4.1)

Yes,

because `list(1,"cat",4.1)` is a collection of values of type integer, character and double.

Is it true that this is an atomic vector?

list(1,"cat",4.1)

No,

because `list(1,"cat",4.1)` is a collection of values of type integer, character and double.

Is it true that this is an atomic vector?

c(1,2,3)

Yes,

because `c(1,2,3)` is a collection of values of type integer.

Is it true that this is an atomic vector?

c("cat","dog","mouse")

Yes,

because `c("cat","dog","mouse")` is a collection of values of type character.

Is it true that this is an atomic vector?

c(2.3,4.1)

Yes,

because `c(2.3,4.1)` is a collection of values of double character.

Is it true that this is a list?

list(1,"cat",4.1)

Yes,

because `list(1,"cat",4.1)` is a collection of values of type integer, character and double.

Is it true that this is a list?

c(1,"cat",4.1)

No,

because `c(1,"cat",4.1)` is a collection of values of type character.

Is it true that this is a list?

list(1,"cat",c(2,"dog"))

Yes,

because `list(1,"cat",c(2,"dog"))` is a collection of values of type integer, character and list.

Is it true that this is a vector?

c(one=1, two=2, three=3)

Yes,

because `c(one=1, two=2, three=3)` is a collection of named/tagged values.

Is it true that this is a vector?

c(one=1, one=2, one=3)

Yes,

because `c(one=1, one=2, one=3)` is a collection of named/tagged values.

Is it true that this is a vector?

list(one=1, one=2, one=c(1,2,"smile"))

Yes,

because `list(one=1, one=2, one=c(1,2,"smile"))` is a collection of named/tagged values.

What is `names(w)` where `w` is

list(one=1, two=2, three=c(1,2,"smile"))

`"one" "two" "three"`

because `names(w)` is a way of asking for the names of `w`.

What is `w[1]` where `w` is

c(1,2,3)

`1`

because `1` is the first element of atomic vector `w`.

What is `w[1]` where `w` is

list(1,2,"3")

`list(1)`

because `1` is a slice of the list `w` containing the first element.

What is `w[[1]]` where `w` is

list(1,2,"3")

`1`

because `1` is the first element of list `w`. More precisely, you can say that it's the first element in the slice of list `w` containing the first element of list `w`.

What is `w[[2]]` where `w` is

list(1,2,"3")

`2`

because `2` is the second element of list `w`. More precisely, you can say that it's the first element in the slice of list `w` containing the second element of list `w`.

What is `w[1]` where `w` is

c(1,2,"3")

`"1"`

because `1` is the first element of atomic vector `w`, and atomic vector `w` contains a value of type character.

What is `w[2]` where `w` is

c(1.0,2,3.0)

`2.0`

because `2` is the first element of atomic vector `w`, and atomic vector `w` contains a value of type double.

What is `w[1]` where `w` is

c(TRUE,2.0,3)

`1.0`

because `TRUE` is the first element of atomic vector `w`, and atomic vector `w` contains a value of type double.

What is `w[[1]]` where `w` is

list(TRUE,2.0,3)

`TRUE`

because `TRUE` is the first element in list `w`. More precisely, you can say that it's the first element in the slice of list `w` containing the first element of list `w`.

What is `names(w[[2]])` where `w` is

list(one=1, two=2, three=c(1,2,"smile"))

`"two"`

because `"two"` is the name of the second element of list `w`.

What is `w[c(1,3)]` where `w` is

c("mercury","venus","earth","mars")

`"mercury" "earth"`

because `"mercury"` and `"earth"` are the first and third elements of vector `w`.

What is `w[c(1,1,2,1)]` where `w` is

c("mercury","venus","earth","mars")

`"mercury" "mercury" "venus" "mercury"`

because `"mercury"` and `"venus"` are the first and second elements of vector `w`.

What is `w[4]` where `w` is

c("mercury","venus",c("earth","mars"))

`"mars"`

because `"mars"` is the fourth element of atomic vector `w`.

What is `w[4]` where `w` is

list("mercury","venus",c("earth","mars"))

`NULL`

because the list `w` does not have four elements.

What is `w[[3]][2]` where `w` is

list("mercury","venus",c("earth","mars"))

`"mars"`

because `c("earth","mars"))` is the third element of list `w` and `mars` is the second element of atomic vector `c("earth","mars"))`.

What is `w[2:4]` where `w` is

c("mercury","venus","earth","mars","jupiter","saturn")

`"venus" "earth" "mars"`

because `"venus"`, `"earth"` and `"mars"` are the second through fourth elements of vector `w`.

What is `w$planet_2` where `w` is

list("planet_1"="mercury","planet_2"="venus","planet_3"="earth")

`"venus"`

because `planet_2` is the name of value `"venus"` in list `w`.

What is `w$planet_2` where `w` is

c("planet_1"="mercury","planet_2"="venus","planet_3"="earth")

nothing

because you cannot use the `$` syntax to refer to a named element of an atomic vector, only a named element of a list.