1661 search results for "time series"

ggplot2: Crayola Crayon Colours

January 21, 2010
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ggplot2: Crayola Crayon Colours

Statistical Algorithms blog attempted to recreate a graph depicting the growing colour selection of Crayola crayons in ggplot2 (original graph below via FlowingData). He also asked the following questions: Is there an easier way to do this? How can I make the axes more like the original? What about the white lines between boxes and

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Announcing r-ORM: A Pure R Object-Relational Mapper

January 5, 2010
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My apologies for the long break between posts. Before the end of this week I’ll return to my series of posts on image processing in R. In the intervening time, I’ve finished a piece of code that I’d like to officially release to the public. The code in question is a very minimal object-relational mapper

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Analyzing a FriendFeed group with Ruby and R

January 5, 2010
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Analyzing a FriendFeed group with Ruby and R

FriendFeed is a social media service, where groups of people can post interesting information from the Web, and "like" or comment posts from others. Statistical Bioinformatician Neil Saunders is a member of the "Life Scientists" group, and has posted an analysis of the group's activity in 2009 to his blog. He used Ruby and the FriendFeed API to extract...

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directlabels: Adding direct labels to ggplot2 and lattice plots

January 3, 2010
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directlabels: Adding direct labels to ggplot2 and lattice plots

Sometimes it is preferable to label data series instead of using a legend. This post demonstrates one way of using labels instead of legend in a ggplot2 plot. > library(ggplot2) > p <- ggplot(dfm, aes(month, value, group = City, colour = City)) + geom_line(size = 1) + opts(legend.position = "none") > p + geom_text(data =

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The Life Scientists at FriendFeed: 2009 summary

December 23, 2009
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The Life Scientists at FriendFeed: 2009 summary

It’s Christmas Eve tomorrow and so I declare the year over. My Christmas gift to you is a summary of activity in 2009 at the FriendFeed Life Scientists group. It’s crafted using R + Ruby, with raw data and some code snippets available. If you want to see the most popular items from the group

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Using Complex Numbers in R

December 18, 2009
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Using Complex Numbers in R

This post is a continuation of my series dealing with matrix operations for image processing. My next goal is to demonstrate the construction of simple low-pass and high-pass spatial frequency filters in R. It’s easy enough to construct simple versions of these filters in R using the Fast Fourier Transform (also known as the FFT),

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Quick Review of Matrix Algebra in R

December 16, 2009
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Lately, I’ve been running a series of fMRI experiments on visual perception. In the interests of understanding the underlying properties of the images I’m using as stimuli, I’ve been trying to learn more about the matrix transformations commonly used for image compression and image manipulation. Thankfully, R provides simple-to-use implementations for all of the matrix

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Because it’s Friday: Detecting Cylons

December 11, 2009
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Because it’s Friday: Detecting Cylons

Battlestar Galactica (Ronald D Moore's reimagined version of the rather cheesy 70's sci-fi series) has been my favourite TV series (of any genre) of recent years, so I'm especially excited that Chris Bilder has given me the chance to blog about it. Chris, an Associate Professor in the Department of Statistics at the University of Nebraska-Lincoln, recently published an...

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APIs: I wish the life sciences would learn from social networks

December 10, 2009
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APIs: I wish the life sciences would learn from social networks

I was prompted by a thread on the apparent decline of FriendFeed to look for evidence of declining participation in my networks. First, a quick and dirty Ruby script, tls.rb to grab the Life Scientists feed and count the likes and comments: #!/usr/bin/ruby require 'rubygems' require 'json/pure' require 'net/http' require 'open-uri' def format_date(d) if d

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Tactical asset allocation using blotter

November 18, 2009
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Tactical asset allocation using blotter

blotter is an R package that tracks the P&L of your trading systems (or simulations), even if your portfolio spans many security types and/or currencies. This post uses blotter to track a simple two-ETF trading system. The contents of this post b...

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