Try R — A new online course, for free • Hacker News Board

Re: Try R — A new online course, for free

#101

Post by xsg » Thu, Dec 06, 2012, 1:32 PM UTC

crowding wrote: post #98

xsg wrote: post #96

Earlier quoted context omitted.

> R is somewhat slower Actually it's MUCH slower, up to a point of being entirely not usable for very large datasets (even ~100GB). True, much of MATLAB speed comes from using highly optimized BLAS (Math Kernel Library by Intel). But not just it. R lacks JIT optimization and numerous attempts to add it were unsuccessful. In fact it's so bad that Ross Ihaka, one of R's creator, proposed to "simply start over and build…

They're both designed around completely in-memory arrays, which are passed around by-value with a copy-on-write scheme. For R there is the bigmem package for mmapped arrays. And the "compiler" JIT packace is included since R 2.13. I've seen that link before. See above re: one group's willingness to talk about the shortcomings versus another organization's preference to paper over it with marketing.

"They're both designed around completely in-memory arrays, which are passed around by-value with a copy-on-write scheme." True, but that doesn't invalidate my point. The datasets I'm typically working with are quite large 300GB-1TB (I have 2TB ram on my main server). I've tried both R and MATLAB and R has been a disaster. Even to plot say 10 million points on a graph is a pain.

Re: Try R — A new online course, for free

#102

Post by hudibras » Thu, Dec 06, 2012, 1:33 PM UTC

crowding wrote: post #97

chernevik wrote: post #66

Earlier quoted context omitted.

How about not-beginners looking to refresh / deepen their intuitions? I've recently been working with the Python toolset in this space -- pandas, numpy, matplotlib -- and run smack dab into my rusty regression analysis. In particular I need to better understand the distribution assumptions underlying the error distributions and the variances around the coefficient and intercept values. Any suggestions for some deeper…

Gelman and Hill is a nice book organized specifically around regression.

Gelman and Hill is a wonderful and under-rated book. My guess is that its clumsy title (Data Analysis Using Regression and Multilevel/Hierarchical Models) hides the fact that it's an introductory textbook that takes the reader from knowing nothing to eventually constructing complex Bayesian models. Plus, it's a pretty good tutorial on R and BUGS.

Re: Try R — A new online course, for free

#103

Post by hadley » Thu, Dec 06, 2012, 1:59 PM UTC

Myrmornis wrote: post #84

hadley wrote: post #70

Earlier quoted context omitted.

Are you using Pandas? If so, your comment would be ironic because pandas borrows heavily from R ;)

What has pandas borrowed from R, other than a 2D data structure with heterogeneously-typed columns? I guess the data frame merge invocations are similar. (I know patsy/statsmodels are introducing R's formula syntax to python, but that's not pandas.)

The split-apply-combine framework dealing with group by tasks (http://www.jstatsoft.org/v40/i01/paper, not that there aren't other precedents) for one. But generally, Wes has used R to figure out what people want to do, and then ported an elegant interface to python.

Re: Try R — A new online course, for free

#104

Post by hadley » Thu, Dec 06, 2012, 2:00 PM UTC

seanlinehan wrote: post #73

hadley wrote: post #71

Earlier quoted context omitted.

Can you give an example where the confusion between a scalar and a length one vector is important? I'm trying to figure out how to better teach R to people familiar with other languages and understanding your stumbling blocks would be v. helpful.

For a strong conceptual grasp of how the language work, I think it is fundamental that students learning R (especially those with a history in other programming languages) understand that there are no scalars in the language. The main argument that I would make for this is that nearly all R functions can operate on vectors with a length grater than one. By understanding that when you send a "scalar" to a function you…

Ah, that makes sense. Thanks!

Re: Try R — A new online course, for free

#105

Post by merlinsbrain » Thu, Dec 06, 2012, 2:40 PM UTC

I was very interested in the course syllabus for 'Statistics One' by Prof. Andrew Conway. I missed the course on Coursera and now I'm unable to view the course archive. Does anyone know where I can find the lectures? (Yes, I've googled some.)

Re: Try R — A new online course, for free

#106

Post by pathy » Thu, Dec 06, 2012, 2:56 PM UTC

kayge wrote: post #22

seanlinehan wrote: post #17

Earlier quoted context omitted.

This is a very, very good point. Though, many of the functions that R provides just won't make any sense at all if you don't have an intuition for the statistics behind it. I have found myself reading the papers published about specific functions in order to understand the results. Do you have any resources that you suggest for beginners in statistics looking to learn on their own?

You probably can't go wrong with the Introduction to Statistics class from Udacity http://www.udacity.com/overview/Course/st101/CourseRev/1

Thanks for the link, I have been meaning to revise some statistics, four years of barely doing any makes you forget a lot.

Re: Try R — A new online course, for free

#107

Post by WinnyDaPoo » Thu, Dec 06, 2012, 4:00 PM UTC

temp453463343 wrote: post #48

WinnyDaPoo wrote: post #46

Earlier quoted context omitted.

Yup, Opera 12.11 on Debian Testing x86_64. _ and - result in - = and + result in + This is so odd...

Oh, I'm on Windows... maybe a platform depended bug?

I'd suspect it could be. It wouldn't be a first for Opera.

Re: Try R — A new online course, for free

#108

Post by aggronn » Thu, Dec 06, 2012, 4:31 PM UTC

prezjordan wrote: post #59

Oh man I really wish I had this at the beginning of the semester. I'm towards the end of a grueling stats course - difficult, and not the best professor. Each homework assignment I feel like I barely scrape by without really learning. This is the first time I've ever felt this way about school.

This has been a very common theme through my undergraduate stats education.

Re: Try R — A new online course, for free

#109

Post by MichaelJW » Thu, Dec 06, 2012, 5:04 PM UTC

merlinsbrain wrote: post #105

I was very interested in the course syllabus for 'Statistics One' by Prof. Andrew Conway. I missed the course on Coursera and now I'm unable to view the course archive. Does anyone know where I can find the lectures? (Yes, I've googled some.)

Take a look here: http://www.universalsubtitles.org/en/teams/coursera/?project...

Credit: http://www.aiqus.com/questions/38783/download-upcoming-cours...

Edit: Is this like posting a pirate link?

Re: Try R — A new online course, for free

#110

Post by frankc » Thu, Dec 06, 2012, 5:10 PM UTC

taeric wrote: post #23

So, I've started using R for some stuff I'm doing at work. I have to say that I'm basically treating it as a non visual spreadsheet. Seems everything I've used it for so far, I could have done with excel. Am I doing it wrong?

Not doing it wrong, but only using a subset of R. For instance, R has powerful data manipulation ability that can get your data to use the subset of R that does what Excel does. R also has a huge library of packages that go way beyond what Excel can do, especially for statistics. Sure, you can do an ols regression in Excel, but you can you do a complicated machine learning model?