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Learner Reviews & Feedback for Getting and Cleaning Data by Johns Hopkins University

6,152 ratings
956 reviews

About the Course

Before you can work with data you have to get some. This course will cover the basic ways that data can be obtained. The course will cover obtaining data from the web, from APIs, from databases and from colleagues in various formats. It will also cover the basics of data cleaning and how to make data “tidy”. Tidy data dramatically speed downstream data analysis tasks. The course will also cover the components of a complete data set including raw data, processing instructions, codebooks, and processed data. The course will cover the basics needed for collecting, cleaning, and sharing data....

Top reviews


Feb 02, 2016

Easy, mostly instructive Course. The Assignments and quizzes are quite good, and illustrates the lessons very well.\n\nSee the videos for general presentation, but use the energy on the excersizes.


Oct 26, 2016

This course is really a challenging and compulsory for any one who wants to be a data scientist or working in any sort of data. It teaches you how to make very palatable data-set fro ma messy data.

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1 - 25 of 921 Reviews for Getting and Cleaning Data

By Bhawesh S

Apr 04, 2019

The course is good but the only problem is there is no explanation on how to solve different problems. there should be a live example of problems so people who have some trouble can get through


Feb 17, 2019

Swirl practice in for Getting and Cleaning Data in this class is terrible. Most of my code working fine in R and R studio but Swirl would tell me "That's not the answer I'm looking for, try again" Then I type "skip()" Swirl will give me the exact answers that I just typed earlier.

By Anthony J M

Feb 01, 2019

There is a huge disconnect with the material and the HAR dataset exercise. I would suggest that there is some help with smaller exercises to help explain how to complete it. Yes, I know you're supposed to do research to help figure out problems, and I have. As a matter of fact, I have taken other courses on data wrangling to be able to figure out this problem. Merging two datasets makes this problem very confusing. Why can't you help guide students through a similar problem, instead of throwing to the fire?

By Mohammad A A

May 13, 2019

There's too much of a jump from the theory to the practice. I had a difficult time understanding what was being asked of me.

By Moshe P

Mar 14, 2019

The material in this course is very condensed. Data Table lecture was very much a copy of someone else' information on the web and was so terse, I would imagine even people from programming backgrounds had had to listen to it many times just to understand what was going . Expect to put in good 8-10 hours a week into this course if you want to become proficient in course' material.

By Pietro P

Jan 26, 2019

Modules 1 and 2 are horrible, so much to cover (several types of files) and so little actual information from the course. Yet, quizzes demand one knows every detail of each file type. Scripts and links are not available from the slides, although I did manage to find a repository with all scripts of the course (after much trouble). Why not make it available from the main page of the course? Anyways, some links were broken and could not be used to follow classes. Classes themselves are very dull, no interaction whatsoever.

By Akshay K

Apr 09, 2018

Week 1 can be more detailed as per what you expect in the quiz. The main idea of following a course is that we get all material about that topic together at one place. But here we are given just names of topics and told to research & read about them ourselves.

By William S

Feb 04, 2018

It's not really acceptable to make students google new things in order to pass the quizzes. Quizzes should asses knowledge gained through the reading and lectures, not our ability to learn via Google.

By Seba L

Jan 12, 2018

The contents of the course are extremely useful. BUT if your programming experience is the two previous courses I think it's a very difficult course, since there are some issues that are outdated or not explained in detail or not explained at all.To do most of the quizzes it's not enough to repeat and listen to the videos. In many cases it's necessary to read a lot of documentation, search and apply new functions that are not explained in the videos, search forums and realize that the packages not work in the same way for the new versions of R, that some functions don't work correctly with RStudio but they do with RGUI, in other cases must be added a certain argument that was not explained in the videos (eg: for windows "binary" mode in the function download.file, which I still have no idea what it means).In short, a lot of things that make certain parts of the evaluations do not measure if you really learned what was taught in the course, but what has been your ability to handle yourself in a self-taught way. Which is a necessary skill in general (not only in R and Data Science) but that isn't what I expect this course teaches me.All this search is more difficult especially for Spanish-speaking people because it isn't enough to have a level in the language between intermediate and advanced, rely on Google Translator and rewind the video many times; to really understand, you have to have some technical language management.

By Alessandro M

Jul 22, 2019

Very good and well done course.

By Courtney P

Jul 17, 2019

Very useful and enjoyable course

By Gabriele R

Jul 15, 2019

Wonderful course, as usual

By Onédio S S J

Jul 13, 2019


By Ussia N

Jul 09, 2019

Equiping me with the skills for my data science career...excellent !!

By Björn L

Jul 08, 2019

Good course which covers quite a lot of material!


Jul 08, 2019

Really helphull

By Lorenzo R

Jul 07, 2019

Some files that were used for the examples were no longer accessible. Updates to the xlsx package also were not reflected or discussed. As I noticed on the forums several students had issues with java dependencies.

By Alfredo L .

Jul 05, 2019

Excelent Course

By Lakshay S

Jul 03, 2019

Course Project was nice.It made me revise the concepts taught in the entire course

By Chirag R

Jun 28, 2019

Good course. Thank you!

By Michele F F

Jun 27, 2019

The best course I have already done about data preprocessing!

By Khaleel u r

Jun 27, 2019

Exceptional by my instructor of this course , very handy

By Ishwarya M

Jun 21, 2019

The course content as well as the assessments are very good. I would recommend this course for everyone who wants to learn Data science

By Ivo G G V

Jun 20, 2019

It needs an update on some libraries.

By Meritxell A L

Jun 17, 2019

I find it very challenging and I learned a lot.