Publications by ellbur
The R WikiBook
Tal Galili, god bless him, is rounding up R bloggers for an R WikiBook In support of this book I am announcing all R-related content I post (here and at the old site) to be available under a cc-by-sa license (not that I’d really care if you didn’t give attribution). Related To leave a comment for the author, please follow the ...
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Items
Let’s define a new pattern! I do a lot of programming for research, and part of what this involves is turning calculations, usually expressed as verbs, into nouns. That is, I need to keep the calculation and all it’s intermediate steps around so that I can inspect them. Alas, I am programming in Python most of the time and end up writing a lo...
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Inheriting in Items
What if we want to extend the behavior of one item with another? Or, to put it another way, what if we want one item to be able to grab the functionality of another? It turns out we can (almost) get this behavior without modifying the item constructor at all. Here’s how you do the grabbing: > grab = function(src, obj=parent.frame()) { > fo...
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Crashed!!
This crashes R (sometimes): 1 2 f = function( 3 a = {x <- y <- z <- w <- t <- u <- 7} 4 ) environment() 5 6 for (i in 1:1000) { 7 try(as.list(f()), silent=T) 8 } 9 10 The problem is the same as I described in the last post Related To leave a comment for the author, please follow the link and c...
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RObjectTables are AWESOME
Why isn’t everyone using the RObjectTables package? This is the best thing ever! Here’s the basic idea of RObjectTables: An environment is an object where you can lookup names and associate them with values. And in particular its where you look up variables used in an expression. But there’s no reason you can’t take any other object that ...
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Reverse Iteration
Time to horrify some people. First let’s include the code we wrote last time, > source(“pretend.R”) and the dependency-tracking environment it creates will be used to run all the following examples. Let’s look at, I don’t know, I’m just trying to demonstrate a language feature so uh… band-pass filtering Gaussian noise. Here’s some...
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You can scrap it and write something better but let me keep R ;)
Ross Ikaha (via Xi’an — thanks 😉 ) gives a nice example to show why R is basically impossible to optimize: > f = function() { > if (runif(1) > 0.5) { > x = 10 > } > x > } x in the last expression could be a local or a global, and this won’t be known until runtime! That’s pretty good. I wonder if this will alw...
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Do older SOers use fewer words?
On StackOverflow, to posters with more experience ask their questions in fewer words? No. There’s no visible difference: Chars of non-code: Chars of code: The data comes from the super-handy StackOverflow API, which was retrieved using wget and then parsed using rjson and XML. First read in and parse the JSON: so.R 1 library(rjson) ...
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