# Posts Tagged ‘ rstats ’

## Transforming a color scale

October 3, 2012
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In developing plots, I often use color (or “colour” in ggplot2 parlance) to reflect values of a third, non-X/Y, variable. Depending on the distribution of this Z variable, however, the effective color range can be narrow, making it difficul...

## A replacement for theme_blank()

October 2, 2012
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ggplot2 has just hit 0.9.2, and with the change comes a new theme system. Previous versions of ggplot2 offered a theme_blank(), which was a stripped-down, essentially blank plotting canvas, but it is now deprecated. github user jrnold has produced a s...

## Making random, equally-sized partitions

October 1, 2012
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Sometimes, as with cross-validation, one needs to generate k partitions, each with an equal number of observations. There are probably an infinite number of ways this could be done in R, but the Gist below illustrates one way to do it in four lines, w...

## Padding integers for use in filenames

September 29, 2012
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If you’ve ever written code that generates a whole whack of files, you may have came across the following problem when processing them. Using a naming convention wherein files are numbered will  gum up any ordering which is based on string sorting (ls, for example). What you end up with is something like this: Which

## Optimal seriation for your matrices

September 28, 2012
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In our previous post, we used a quick-and-dirty method for ordering the axes on our heatmap. It has been pointed out to me that There is a Package for That (which is my nominee for a new slogan for R — not that it needs a slogan). seriation offe...

## Continuous dispersal on a discrete lattice

September 27, 2012
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Dispersal is a key process in many domains, and particularly in ecology. Individuals move in space, and this movement can be modelled as a random process following some kernel. The dispersal kernel is simply a probability distribution describing the distance travelled in a given time frame. Since space is continuous, it is natural to use

## Simplest possible heatmap with ggplot2

September 27, 2012
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Featuring the lovely “spectral” palette from Colorbrewer. This really just serves as a reminder of how to do four things I frequently want to do: Make a heatmap of some kind of matrix, often a square correlation matrix Reorder a factor vari...

## Merging Data Sets Based on Partially Matched Data Elements

September 26, 2012
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A tweet from @coneee yesterday about merging two datasets using columns of data that don’t quite match got me wondering about a possible R recipe for handling partial matching. The data in question related to country names in a datafile that needed fusing with country names in a listing of ISO country codes. The original

## Modifying select off-diagonal items in a matrix

September 25, 2012
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This is something I have had the occasion to do, and never remember how, so this is legitimately a reminder to my future self of how to do things with off-diagonal elements of a matrix. Select rows and columns are easy: mat or mat, for...

## Visually-weighted regression plots, with Zelig

September 25, 2012
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As a follow-up to yesterday’s post on producing visually-weighted regression plots, here is some code which illustrates the production of similar plots, but using Zelig’s convenient modeling and simulation functions. This code was produced...