Question

______  let’s you perform SQL queries on your R data frames.

(a) sqldf

(b) plyr

(c) forecast

(d) daply

I had been asked this question in an online interview.

I'd like to ask this question from Packages in chapter Commands, Packages, Visualizing Data and Linear Regression of R Programming

Answer 1

Right choice is (b) plyr

To elaborate: sqldf uses SQLite syntax. Plyr will split-apply-combine paradigm for R. Forecast is a generic function for forecasting from time series or time series models. The function invokes particular methods which depend on the class of the first argument.