Question

Which of the following sort a dataframe by the order of the elements in B?

(a) x[rev(order(x$B)),]

(b) x[ordersort(x$B),]

(c) x[order(x$B),]

(d) x[rev(x$B),]

The question was posed to me in a job interview.

Question is from Commands topic in section Commands, Packages, Visualizing Data and Linear Regression of R Programming

Answer 1

Correct option is (a) x[rev(order(x$B)),]

To elaborate: x[rev(order(x$B)),] sort the dataframe in reverse order.