The bulkreadr package, an ultimate tool for reading data in bulk is now on CRAN
The following places are good to learn data science:
Lecture notes Master Data Analysis r-statistics Machine learning tutorial Big data made simple SQL and Pandas tutorial Suzan Baert excel2r ggplot2 in Python Data mentor Data Skills seaborn tutorial STHDA tutorialspoint Introductory Econometrics
Listen data HighlandR GitHub data.table for Python Beginner's guide