Vagrant is a tool that you can use to set up, configure, and access a VM through the command line. This is a life changer. I love it. In this post I’ll walk through setting up an OEL6 virtual machine, installing a non-ancient version of Python, and configuring the port forwarding so that you can use it for backend web development. (The port forwarding is not obvious on RHEL/OEL.)
Using simpleldap
Recently, I thought I needed to use simpleldap–it turned out that I instead needed to reconfigure NGINX. At any rate, this was my experience with simpleldap.
Direct and Delegated Event Handlers in jQuery
An alternate title might be: how to bind event handlers to new, or dynamically generated, table rows. When using jQuery, we attach sets of instructions to different parts of an HTML document using selectors. Suppose you wanted to attach some functionality to some text in a table, for example, when you click on a row in a table, it brings up a new table below the first table. This is actually kind of tricky, it turns out that there is a distinction between direct and delegated event handlers.
Using PyWavelets to Remove High Frequency Noise
I ran across an interesting blog post from 2012 that described how to use the PyWavelets module to remove noise from signals. I had been looking for a technique for smoothing signals without smoothing over peaks and sharp shifts, and I had completely forgotten about using wavelets.
Using Sessions in Flask
In this post I’ll provide an example of using session management in Flask. This is useful when you need to recover persistent data across different endpoints in your application. In this example, we set the permanent attribute of the session object to True in order to ensure that the session data lasts indefinitely until it is cleared when the user accesses the root endpoint again. The best practice is to have a timeout on the session data.
Scraping Yahoo! Finance Data with BeautifulSoup
This weekend I wanted to work on collecting and plotting historical option contract prices. I used the following API call to pull option contract data from Yahoo!
curl -X GET "http://finance.yahoo.com/q/op?s=AAPL&m=2016-01" | cat > aapl
Using SVGs in IPython Notebooks
Sometimes I like working directly with SVGs in order to generate images from code. I like using the IPython Notebook for this because of the instant feedback. Here is an example for creating and viewing a small SVG within the IPython Notebook.
Swift Optimization
I learned a hard lesson today: to make Swift really fast you have to know what you’re doing. You can’t just slap some code together and expect it to be zippy without understanding some of how Swift was designed and how it works. There is a very good presentation by some of the team members that built Swift here. My initial takeaway was that it was important to finalize any classes you didn’t plan on subclassing, incrementally check the timing analyzer, and finally, employ whole module optimization.
Running Nosetests with Multiple Versions of Python
This is a short post–just a TIL sort of thing. I had an issue today where the system Python was 2.6, but I needed to run a test on some code that used Python 2.7. After some jiggering I figured out how to test my Python 2.7 code. Rather that simply running,
nosetests tests.py
I ran, instead,
/usr/local/bin/python2.7 /usr/bin/nosetests tests.py
Boom. Now we’re testing.
Cocoa REST Client
Here’s an awesome thing: an easy-to-use, free, open-source, native OS X app for testing HTTP/REST endpoints. You can even save common calls for future reference. Check out mmattozzi‘s cocoa-rest-client right now. (Seriously, stop what you’re doing.)