# 2486 search results for "twitteR"

## (Almost) Friday Function: alarm

April 21, 2011
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Last week I decided to start a weekly column detailing an interesting function each Friday, entirely forgetting that I would be on holiday, without internet access (shock horror!), tomorrow. So here’s your column a little early. The alarm function is something of a novelty, in that all it does is to make an annoying noise

## supercalifragilisticexpialidocious = 1

April 21, 2011
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I notice that the latest version of R has upped the maximum length of variable names from 256 characters to a whopping 10 000! (See ?name.) It makes the 63 character limit in MATLAB look rather pitiful by comparison. Come on MathWorks! Let’s have the ability to be stupidly verbose in our variable naming! Tagged:

## Non-standard assignment with getSymbols

April 21, 2011
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I recently came across a rather interesting investment blog, Timely Portfolio. I have a certain soft spot for that sort of thing, because using my data analysis skills to make a fortune is casually on my to-do list. This blog makes regular use of a function getSymbols in the quantmod package. The power and simplicity

## ARMA Models for Trading, Part II

April 20, 2011
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We left the last post at the point of determining the best ARMA model. Before continuing the discussion, however, I would like to make a few points that might seem a bit questionable or unclear: We model the daily returns instead of the prices. There are multiples reasons: this way financial series usually become stationary,

## Aggregate Function in R: Making your life easier, one mean at a time

April 20, 2011
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I previously posted about calculating medians using R. I used tapply to do it, but I’ve since found something that feels easier to use (at least to me). ?Download download.txt1 2 3 aggregated_output = aggregate(DV ~ IV1 * IV2, data=data_to_aggregate, FUN=median) aggregated_output The above code saves an aggregated dataset to aggregated_output and gives you the

## Export a Table Created by R to a TeX File

April 17, 2011
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Producing tables in LaTeX might be a difficult task as we can not just copy and paste a table in the editor; we have to write all the numbers and other codes. But with the help of xtable package of R it is possible to produce all the necessary codes for producing table in LaTeX and also possible to...

## Introduction to Cointegration and Pairs Trading

April 15, 2011
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Introduction Suppose you see two drunks (i.e., two random walks) wandering around. The drunks don’t know each other (they’re independent), so there’s no meaningful relationship between their paths. But suppose instead you have a drunk walking with her dog. This … Continue reading →

## Friday Function: setInternet2

April 15, 2011
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Corporate IT networks are a pain for programmers. Ideally, when programming, you want the freedom to download, install and run any software that you want. Unfortunately, in the interests of security, many programmers find themselves a little restricted at the office. (I’m sure that many network admins will protest that the situation works both ways

## R 2.12 to 2.13 package upgrade

April 14, 2011
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If you: use Linux have just upgraded your R installation from 2.12 to 2.13 installed some/all of your packages in your home area (e.g. ~/R/i486-pc-linux-gnu-library/2.12) and… …are wondering why R can’t see them any more just do this: # at a shell prompt cp ~/R/i486-pc-linux-gnu-library/2.12 ~/R/i486-pc-linux-gnu-library/2.13 # in R console update.packages(checkBuilt=TRUE, ask=FALSE) # back to