Computer Programming

Yes, a bit specific, but I need to store some links!

R Database Connection Class in RS (R5 S5)

I'm learning R, and it's been interesting. The weird part is that I don't know stats. Yes, I know standard deviation, mean deviation, and easy stuff, but those are one-liners in the R tutorials. What I know in stats amounts to around 1/4 to 1/2 a page of the R tutorial. So to compensate, I have a stats text from the thrift store, so I'll eventually be less than a total ignoramus about what I'm reading.

One of the twists of what I'm messing with is that all our data is in a database. The normal mode of operation for R users is to load the entire data table into memory and do awesome reporting on it. Where I'm at, for better or worse, is more like a traditional web application with a database back end.

A problem with this is that MySQL lets me have only 16 connections going at the same time. I'm not sure if it's the driver, but I'll assume that. Since RStudio holds the connections, coding a lot of changes eventually leads to a lot of lost database connection handles, and eventually running out of connections.

Installing R Packages Globally (for rApache)

For general instructions, see: http://cran.r-project.org/doc/manuals/R-admin.html#Managing-libraries.

In Ubuntu Linux, the path to the global libraries is: /usr/local/lib/R/site-library/

To install there, you can do install.packages(c('foo'), '/usr/local/lib/R/site-library/')

or take advantage of the built in variable: install.packages(c('foo'), .Library.site[1])

Check that .Library.site has the values you need.

You can also use R CMD INSTALL -l /path/to/library foo

PHP with More Coolness

A short article explaining how to improve your experience and produce slightly better code.

URLs: it's important to define your URLs rather than exposing all your PHP files to the world.

Use routes - study the one in ZF2 but don't copy it unless you really need it. CodeIgniter's is pretty nice too. Routes help map URLs to classes and methods.

If you don't want to use routes, use Apache's mod_rewrite. It's faster, and also awesome. It tranforms specific URL into specifc requests to specific scripts.

PHP with Less Risk

An extremely short article about how to avoid pitfalls that will get you hacked. I've been hacked, so I kind of know this from experience.

CSS Hints for Technoids Who Forgot to Learn CSS

This article is being rewritten. If you want the latest, contact johnk at this domain.

The original was written: 2004-11-18 03:16:46 -0700.

Here's a bit of the article:

Dang, but it took me forever to learn CSS. Maybe I should have used a book. Here, I'm going to share with you the hard-found knowledge, presented using technical programmer jargon. (Revised in 2014.)

What is Cascading Style Sheets (CSS)? The typical answer is that it's a way to separate the way a page looks from the the underlying HTML, which describes the structure of the document.

Rich Text Editors for Email, in HTML Browsers

I've been working on this email layout hack, and started to build it from content, and came to the inevitable conclusion that email and web are two different media.

CSS Stylesheet Switcher Widget

This snippet of code can be modified and used to change the stylesheet on your page. I set it up to work against a layout extracted from Salsa, but it should work on generic pages. It's good for demos, discussions about a layout, trying different colors, etc.

Tiny Javascript Cookie Library

This is one of those "why bother with an external library" moments. Mostly copied from MDN.

TPCalc for Android

A while back, I made a little program called TPCalc to do one of my favorite mundane activities, which is to determine the best price for toilet paper at

Notes

I got the ezmlm migration working, which is cool. Mailman and mail migration will be easier. So I took a day off. (Web migration will be a headache.)

Rewriting Code

There is no great writing, only great rewriting. - Justice Brandeis

I'm not much of a Python coder, but I'm learning to be a pretty good Python re-coder.

Button to Scroll to Top of the Page

Mobile websites all seem to have this button, which appears when you've scrolled down a bit. The button scrolls you back to the top of the page, where most of the menus reside.

Converting Time or Datetime to UTC in Python

This seems so basic, it's almost embarrassing to publish, but this showed up a few times on Stackexchange. I had trouble figuring it out, too, partly because the Python docs are so lengthy.

Exception - what is it?

What's an Exception?

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