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I’m Wendy Liu, and I’m currently the CTO of Macromeasures, a data science startup that I co-founded after graduating from McGill University in 2014.

In case you’re wondering about the username: I have no affiliation with Dell Inc; “dellsystem” is an unfortunate consequence of a decision I made when I was 12, when I signed up for an account on phpbb.com so I could get support for my phpBB installation. Since I was using a Dell computer at the time, “dellsystem” seemed like a reasonable choice for what I thought would be a throwaway account. I was wrong about the throwaway part, as the phpBB community turned out to be a gateway drug for open source software and programming in general. I have since come to terms with the username “dellsystem” and will even answer to “dell”.

Below, you’ll find excepts of my most recent blog posts (you can view them all on the writing page). If you want to get in touch, find me on Twitter @dellsystem, or check out my about page for other contact options.


A change of pace

February 3, 2017 :: Categories:

When I first created this blog – almost six years ago, somehow – I planned to fill it with technical posts about projects I was working on and tips I’d discovered. It only recently occurred to me that I, despite being a programmer by occupation, could use my blog to write about things other than programming. Which is silly, because it’s not as if I had been born with a fully-formed .vimrc file ... Read more »

Predicting the U.S. election without polls

November 18, 2016 :: Categories:

A few days after the United States presidential election, Data Driven Journalism featured a great piece about the pitfalls of relying on opinion polls to predict elections: “Will data driven election reporting ever be the same?” I myself had fallen into the trap of trusting the polls that predicted a landslide Clinton win, so in the aftermath of the unexpected election results, I started thinki... Read more »

Time-slicing photos with Python and ImageMagick

May 15, 2016 :: Categories: ,

I recently came across a neat example of time-slice photography, which featured the Manhattan skyline over a period of 30 minutes around dusk. It’s a really cool technique that I’ve always wanted to try reproducing through paint, since the nature of the medium means you could make the slices blend together more seamlessly than would be possible in a photograph. So that became my next art proje... Read more »

psycopg2 OFFSET performance with large tables

April 23, 2015 :: Categories: ,

This post is about solving a minor performance issue that can be encountered when using psycopg2, a commonly-used Python driver for PostgreSQL. It will likely be of zero interest to you unless you have come across this problem before. Even then, it is doubtful that it is worth reading all the way through unless you have this problem *right now* and don’t mind wading through excessively flowery ... Read more »

Showing only additions and deletions in git

April 18, 2014 :: Categories:

If you’ve ever been in a situation where you wanted to see only the additions, or only the deletions, in a git diff, then you probably know that it’s not as simple as running git diff --diff-filter=A or git diff --diff-filter=D. At least, not if you’re looking for added or deleted lines, as opposed to files. From the man page for git diff: --diff-filter=[ACDMRTUXB*] Select only files that ... Read more »


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