Question

R programming: provide code and explanation

b. -Here's an integer vector . what happens if you ins ert NULL into the 4th position of the vector ?- irJ a <-1:10 print (a)

Answer 1

b.

If we try to insert NULL value to the 4th position in the vector, we get an error.

> a<-1:10
> a[4] <- NULL
Error in a[4] <- NULL : replacement has length zero

NULL is a zero length special object in R. We cannot assign this object to a specific element of a vector object in R. You may however assign it to the vector object itself.

16.

<- operator is used to assign variable in the same environment

<<- operator is used to assign variable in the global environment

For e.g.

Using the global environment assignment operator

> x <<- 10

Below is a function which assigns value to x in its local environment using <- operator

> test <- function(y) {x<- y
+ print(x)}
> test(2)
[1] 2

Now if we print x, the value from the global environment would be printed.

> print(x)
[1] 10

15. Yes we can have a data frame with 0 rows and 0 columns.

> df <-data.frame()
> df
data frame with 0 columns and 0 rows