I thought it might be fun to post a J vs R side-by-side comparison. The character counts aren't meant to be exact... The solutions are fairly similar up until the moving averages. It wasn't meant as a code golf exercise.
http://jsbin.com/ihunin/337 After reading R code for years, I actually think the J version is more pleasant to look at I'd like to add an example where J really shines over R. The data.table package in R makes it much more succint than normal R code. The most stark example I came up with so far is the moving average. Are there any other ideas? There's probably a more concise way to express this too: plot > 20%~ each +/"1 each _20 <\ Prices I thought I could get atop or something to work but I gave up after about 10 minutes. On Mon, Feb 17, 2014 at 12:59 PM, Joe Bogner <[email protected]> wrote: > Here is the code: > > NB. retrieve stock prices from yahoo and do some graphing > load 'web/gethttp' > load 'tables/csv' > load 'plot' > > URL=:'http://ichart.finance.yahoo.com/table.csv?s=' > > quote=: 3 : 'fixcsv gethttp URL,y' > > Quotes=: quote each 'DAL';'UAL' > > 'DAL UAL'=:Quotes > > DALd =: |. }. DAL > > Prices=: > ". each 4{"1 DALd > plot Prices > > MaxPrice=: >./ Prices > > plotPrices =: 3 : 0 > pd (i. # y);(|. ,> y) > ) > > plotTickers =: 3 : 0 > Tickers=.y > pd 'reset' > pd 'key',(, > ' '&, each Tickers) > Quotes=.quote each Tickers > AllPrices=. ". each > }. each 4{"1 each Quotes > plotPrices"1 AllPrices > pd 'show' > ) > plotTickers 'UAL';'DAL';'JBLU' > > Years=. 4 {. each 0{"1 DALd > groupBy=: 4 : '(((~.y) i. y)) ,/. x' > YearGroups=:Prices groupBy Year > MaxPricePerYear =: >. /"1 YearGroups > ]YearKeys=: ". > ~. Year > plot YearKeys;MaxPerYear > > > > > > On Mon, Feb 17, 2014 at 12:49 PM, Joe Bogner <[email protected]> wrote: > >> This is a continuation of this thread: >> http://jsoftware.com/pipermail/programming/2014-February/035222.html but >> moved to chat. >> >> I posted a video http://www.youtube.com/watch?v=qXFpgYvbogw with the >> intent of showing some of J's capabilities. >> >> I would be happy to hear any feedback on the video. >> >> Looking back at it, I wish I bumped up the font size. It's best viewed >> full screen. >> >> I tried to flip through things pretty quickly to fit in as much as >> possible. I probably unnecessarily explained things in a few cases. I >> still need to practice using the right term for the operations too. >> >> In terms of my examples, I would like to know if I could put dates >> somehow on on X-axis. >> >> I also worked up an example that used a secondary axis with % change, but >> I haven't recorded it yet. That might be a continuation. Plotting on a >> secondary axis is something that J's plot does real easily compared to R. >> >> Thanks for any feedback >> > > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
