November 2012

Opting for shorter movies, be aware u might be cutting the entertainment too!

November 23, 2012 |

Hello Friends,This time I thought to bring in little more spice and thought of focusing on movies.  I don’t know about you but I am a movie buff. Often on a weekend when I am trying to pick up a movie from my movie repository, which spans to ... [Read more...]

xts and GSOC 2012

November 23, 2012 |

Josh Ulrich and Jeff Ryan mentored a Google Summer of Code (GSOC) project this summer focused on experimental functionality for xts in collaboration with R. Michael Weylandt, a student in operations research and financial engineering from Princeton. You might recognize Michael from his presentation at R/Finance this year, where ... [Read more...]

ggplot2 Tutorial

November 23, 2012 |

Here is a link to a wonderful ggplot2 tutorial: http://www.ceb-institute.org/bbs/wp-content/uploads/2011/09/handout_ggplot2.pdf by R. Saccilotto and the Basel Institute for Clinical Epidemiology …Continue reading » [Read more...]

IPython vs knitr, or Python vs R

November 23, 2012 |

I watched this video by Fernando Pérez a few days ago when I was reading a comment by James Correia Jr on Simply Statistics: This is absolutely a fantastic talk that I recommend everybody to watch (it is good in both the form and content). Not surprisingly, I started ...

project euler: problem 61

November 22, 2012 |

Triangle, square, pentagonal, hexagonal, heptagonal, and octagonal numbers are all figurate (polygonal) numbers and are generated by the following formulae: Triangle P3,n=n(n+1)/2 1, 3, 6, 10, 15, ... Square P4,n=n2 1, 4, 9, 16, 25, ... Read More: 1439 Words Totally [Read more...]

Escaping the simplex, part 1

November 22, 2012 |

Before tackling the main subject, two quick notes:I did not post for quite a while in part because I followed the Coursera online course Introduction to Computational Finance and Financial Econometrics.  It was a nice refresher, extremely well pre... [Read more...]

Peer-reviewed R packages?

November 22, 2012 |

Dear R-Users, a question: I am the author of the ‘qpcR’ package. Within this, there is a function ‘propagate’ that does error propagation based on Monte Carlo Simulation, permutation-based confidence intervals and Taylor expansion. For the latter I recently implemented a second-order Taylor expansion term that can correct for nonlinearity. ... [Read more...]

nice ggplot intro tutorial. Just run the commands, about 6 pages…

November 22, 2012 |

nice ggplot intro tutorial. Just run the commands, about 6 pages = flexible 1-3 hours of learning, depending how much reading you want to pair it with by Ramon Saccilotto [Read more...]

We NEED more data

November 22, 2012 |

Email One of the historic difficulties of doing research on urban energy systems has been the limited availability of data at sufficiently detailed spatial resolutions. Without this data, you might end up relying on aggregate information about the built environment, building occupants, and local geography that doesn't apply to the ... [Read more...]

Washington Gave Thanks To R:

November 22, 2012 |

The folks over at is.R() brought along an "adorable Turkey". I guess we'll thank them for their gift - and pardon the Turkey. Personally I thank them for a bucket of hints and tricks I freely used and will continue to do so.Tal brought us a great ... [Read more...]

Connecting R to an Oracle database with RJDBC

November 22, 2012 |

In many circumstances, you might want to connect R directly to a database to store and retrieve data.  If the source database is an Oracle database, you have a number of options: ROracle RODBC RJDBC   Using ROracle should theoretically… Read more › [Read more...]

Controlling heatmap colors with ggplot2

November 22, 2012 |

One of the most popular posts on this blog is the very first one, solving the issue of mapping certain ranges of values to particular colors in heatmaps. Given the abundance of ggplot2 usage in R plotting, I thought I’d … Continue reading → [Read more...]

Happy Thanksgiving from is.R()!

November 22, 2012 |

Today’s post is mostly to wish everyone a Happy Thanksgiving. We will be taking the rest of the week off, and will return on Monday. Below is some code to reproduce the adorable Turkey above; enjoy! https://gist.github.com/4122464 [Read more...]

Extending Commodity time series

November 21, 2012 |

I want to follow up with Extending Gold time series post by showing how we can extend Commodity time series. Most Commodity ETFs began trading in 2006, please see the List of Commodity ETFs page. I will use DBC – PowerShares DB Commodity Fund, one on the most liquid Commodity ETFs as ... [Read more...]

What’s the difference between POSIXct and POSIXlt?

November 21, 2012 |

POSIXct is the signed number of seconds since “the epoch”. For example it was 1351298112 UTC (GMT) when I wrote this. (1351298112 UTC = Sat Oct 27, 2:35 am GMT = Fri Oct 26, 8:35 pm EST = Fri Oct 26, 5:35 pm PST = 2:35 pm HST) POSIXlt is one of many text | character | string formats such as: May 17, 2017 17/5/2017 17-5-17 05:24:39 [Read more...]

Data types, part 3: Factors!

November 21, 2012 |

In this third part of the data types series, I'll go an important class that I skipped over so far: factors.Factors are categorical variables that are super useful in summary statistics, plots, and regressions. They basically act like dummy variables t... [Read more...]

Upcoming Webinar: Real-time, big-data analytics

November 21, 2012 |

A quick heads-up that I'll be presenting another brand-new webinar on Thursday next week (November 29). In Real-time Big Data Analytics: From Deployment to Production, I'll review the process of making predictive models work in real-live operational environments. I'll also tackle those ubiquitous buzz-words "real-time" and "big data", and the fact ... [Read more...]

IPython vs RStudio+knitr

November 21, 2012 |

At a meeting last night with some collaborators at the Vélobstacles project, I was excitedly told about the magic of IPython and it’s notebook functionality for reproducible research. This sounds familiar, I thought to myself. Using a literate programming approach to integrate computation with the communication of methodology ... [Read more...]

Representing density in two dimensions

November 21, 2012 |

I’ll be subbing today for Chris, as we continue to explore some ggplot2 basics. Today, imagine that you have data distributed in two dimensions, and that you would like to convey differences in point density over space. As with many things, this... [Read more...]

Creating an R package in Windows

November 21, 2012 |

[caption id="attachment_411" align="aligncenter" width="500"] A nice package can be both beautiful and functional. The image is CC by MIAD Communication Design.[/caption] Inspired by this post by Szilard Pafka I decided to do a similar adventure in a Windows environment and see what problems I run into. Start ... [Read more...]
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