## ggplot2 Tutorial

November 23, 2012
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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 »

## IPython vs knitr, or Python vs R

November 23, 2012
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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 thinking ipython vs knitr. Corey Chivers said we could...

## project euler: problem 61

November 22, 2012
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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 ...

## Escaping the simplex, part 1

November 22, 2012
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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...

## Peer-reviewed R packages?

November 22, 2012
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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. The formulas are quite complex

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

November 22, 2012
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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

## We NEED more data

November 22, 2012
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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 specifics of a particular neighbourhood

## Washington Gave Thanks To R:

November 22, 2012
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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 ...

## Connecting R to an Oracle database with RJDBC

November 22, 2012
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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 ›

## Controlling heatmap colors with ggplot2

November 22, 2012
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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 →

## Happy Thanksgiving from is.R()!

November 22, 2012
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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

## Extending Commodity time series

November 21, 2012
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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 my proxy for

## What’s the difference between POSIXct and POSIXlt?

November 21, 2012
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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

## Data types, part 3: Factors!

November 21, 2012
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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...

## Upcoming Webinar: Real-time, big-data analytics

November 21, 2012
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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 that they can mean very different things in...

## IPython vs RStudio+knitr

November 21, 2012
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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 and results has been at the core

## Representing density in two dimensions

November 21, 2012
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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...

## Creating an R package in Windows

November 21, 2012
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A nice package can be both beautiful and functional. The image is CC by MIAD Communication Design. Inspired by Read more »

## Fun with coin flips

November 21, 2012
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We all know that the odds of flipping an unbiased coin is 50% heads, 50% tails. But what happens if you do this a lot of times. Do you expect the same number of heads and tails? What if we took a cumulative sum where heads = +1 and tails = -1. What wou...

## Video: SimpleR tricks and tools: Help, debugging, git, LaTeX, and workflow with R by Prof Rob Hyndman

November 21, 2012
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This post shares the video from a talk presented on 20th November 2012 by Professor Rob Hyndman at Melbourne R Users. The talk provides an introduction to: Getting R help Debugging R functions R style guides Making good use of … Continue reading →

## Rcpp attributes: A simple example ‘making pi’

November 20, 2012
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We introduced Rcpp 0.10.0 with a number of very nice new features a few days ago, and the activity on the rcpp-devel mailing list has been pretty responsive which is awesome. But because few things beat a nice example, this post tries to build some more excitement. We will illustrate how Rcpp attributes makes it really easy to add C++ code...

## R User Conference in Spain: Call for Tutorials

November 20, 2012
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I'm really looking forward to useR! 2013 (the international conference for R users), and not just because it's being held in Spain next year (July 10-12). The program is already coming together, with a great lineup of invited speakers, including R-core member Duncan Murdoch and prolific package authoR Hadley Wickham. You too can be part of the program, by...

## optimising accept-reject

November 20, 2012
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$optimising accept-reject$

I spotted on R-bloggers a post discussing optimising the efficiency of programming accept-reject algorithms. While it is about SAS programming, and apparently supported by the SAS company, there are two interesting features with this discussion. The first one is about avoiding the dreaded loop in accept-reject algorithms. For instance, taking the case of the truncated-at-one

## Functional programming with lambda.r

November 20, 2012
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$Functional programming with lambda.r$

After a four month simmer on various back burners and package conflicts, I’m pleased to announce that the successor to …Continue reading »

## SimpleR tips, tricks and tools

November 20, 2012
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I gave this talk last night to the Melbourne Users of R Network. Examples

## Claims reserving in R: ChainLadder 0.1.5-4 released

November 20, 2012
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Last week we released version 0.1.5-4 of the ChainLadder package on CRAN. The R package provides methods which are typically used in insurance claims reserving. If you are new to R or insurance check out my recent talk on Using R in Insurance.The chain-ladder method which is a popular method in the insurance industry to forecast future...

## Heteroskedastic GLM in R

November 20, 2012
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A commenter on my previous blog entry has drawn my attention to an R function called hetglm() that estimates heteroskedastic probit models. This function is contained in the glmx package. The glmx package is not available on CRAN yet, but thankfully can be downloaded here. The hetglm() function has a number of computational advantages compared with

## Prime Factorization Visualization with R and Shiny

November 20, 2012
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Quite a lot of people have had fun recently with prime factorization. It all started on The Math Less Traveled, then various versions of the prime factorization diagrams appeared (here, here, this animated one, etc., they are actually more or less listed here). So I wanted to have fun too and give a try...

## Project Euler — problem 24

November 20, 2012
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It’s a lovely day. I took a walk around the campus after lunch. The scene was enjoyable in one deep autumn day. Before the afternoon work, I’d like to spend a few moments on the 24th Euler Problem. A permutation is an ordered arrangement of … Continue reading →