Every day, Python is the primary programming language for tens if not hundreds of thousands of professional engineers, analysts, and researchers, including yours truly. Given Python's "language of choice" status, what can you do to join those lucky ranks?
It's a good question, and one I get often. Recently I was asked more publically than usual. Michael Kennedy, host of the Talk Python to Me podcast, asked me five questions on behalf of people early in their Python/programming careers:
Here are my answers, the enterprise hiring perspective, as transcribed from my parts of the panel discussion.
Hi my name is Mahmoud Hashemi. I'm lead developer of Python Infrastructure at PayPal, and I'm also the presenter of Enterprise Software with Python, coming soon from O'Reilly. Dedicated listeners may recognize my voice from episode #4 of Talk Python to Me, and it's great to be back on the show.
What kind of Python devs do you work with and interview?
I work with Python infrastructure engineers. Software infrastructure is the foundation of all sorts of software development, from web to backend to batch to automation and tools. To do it well you have to have personal experience developing in two or more of those categories. For the past year or so, my team has been adjunct to the PayPal application security team, and that's who I'm hiring for right now. So a little plug, if you have at least five years of industry experience and want to get into some ultrahigh performance Python security work, shoot me an email at email@example.com.
All that said, one of the services the Python infrastructure team also performs is to do phone and in-person interviews for PayPal teams looking to expand their Python talent through hiring.
What is the most important piece of experience that you look for in a candidate?
The most important fundamental skills I look for are closely related to experience: environmental fluidity and personal learning abilty.
Wait, not Python? That's right. The fact is, for more junior jobs, the Python is going to be the easiest part of the job, and new hires have plenty of time to learn, plus the team is there to help. New developers will come up to speed quickly provided they're comfortable learning in the environment.
As for environmental fluidity, specifically, PayPal uses a lot of Linux, so I look for candidates that can demonstrate familiarity at the console, interacting with the operating system. So while I don't usually give candidates complex algorithmic questions on the spot, I do log them into one of PayPal's test servers and have them do some basic debugging. For the experienced, you can almost feel them relaxing into a familiar environment. For the inexperienced, the terminal can be an aptly named dark and scary place. Either way, the command line is a foundational technology critical to enterprise work, and is not going away anytime soon. Lack of command line comfort is a big yellow flag, especially when Linux is so widespread and easy to experiment with on your own.
The other characteristic I look for is learning ability. The skills to read and research naturally, absorbing and arranging information automatically. I've been burned once or twice by talented people who were too lazy to read the docs, or too intimidated to read the source code. You don't have to do it in big gulps, but you do need to do it consistently. So I usually look at what candidates have done to learn lately, and the sources they've been consulting. Show me some code you've written and what you learned during the process. Tell me about a project that sounds much simpler than it was. What sites taught you the web? Seen any noteworthy source code lately?
On the other hand, I watch out for HackerNewsy types. My projects have topped HN several times in the last couple years, and some lurking is fine, but I want someone ready to outgrow that consumption and commodification of creative work interleaved with press releases. Someone ready to dedicate time to actually create the sorts of things that others will upvote.
If someone is applying for their first job with you, what can they present to show they have the right skillset/education?
When it comes to first jobs and concrete projects, I'll look at anything and everything. With new developers it's just so rare to get someone with anything interesting in their GitHub or Bitbucket account, but that is definitely my first stop. Software is increasingly portfolio driven, and I do get a bit discouraged when I see a developer who doesn't have a GitHub, or a site, or even a blog. You can cram for an interview, and you can exaggerate on a resume, but you can't really fake a meaningful commit timeline going back a year or two. Even if it's just school projects, at least I could see you've tried and you have some basic git skills. Contributions to other projects tell a good story, too. You were probably using the project for something, being productive. You took the time to understand how it worked, you were able to communicate, and lived up to someone else's standards. That's stressful for a lot of people, but that's got a lot in common with enterprise development, too.
Side projects and apps that run in environments similar to our own are very interesting. Mobile phone apps not as much. Code competitions and scores from reddit/stackoverflow/HN are OK, but honestly those skills don't apply that well internally. This may make me unpopular, but people who have high scores on all those sites are playing games that can lead them to be impatient and unhelpful with internal people and processes. That said, if you're someone who helps out with mentorship or even get on IRC and answer questions, that could be great!
If you are presented with two candidates, one with a solid CS degree, and the other with 1-2 years of experience, which would you value more?
Of the three hires I'd truly consider my "star" hires, none of them had a CS degree. Electrical engineering, math, and comparative literature. The things they had in common were voracious reading and extensive hours spent in some Python or POSIX environment.
Computer science degrees aren't really necessary for the majority of enterprise work. Like I said before, environmental fluidity and willingness to read docs are far more important. A couple of CS classes get you some useful vocabulary and teach you time complexity.
As for the concept of a degree in general, if you want to work at a big company, it's a lot easier to get in with a bachelors. You don't need much more than that. The right two years of experience can go a long way in terms of skills development, but in terms of management marketability, no degree raises eyebrows in many cases. So, in short, for enterprise software, my observation is that a computer science degree is about as good as a non-CS degree plus 2 years experience which is about as good as no degree plus 4-5 years experience, at least.
Most professors and academic programs don't give you all that much pragmatic knowledge, even if it's pretty old stuff like emacs and terminal usage. Basically everything is about how you approach your assignments and free time. If you push beyond the requirements, you will learn much more.
So, if you're in school, take an operating systems class. Take a networking class. Maybe a crypto class. You'll learn almost as much as running a shared server in your dorm. No, those are different types of knowledge, so consider doing both. If you're not in school, Coursera and other options are far better than nothing, and I'd like to hear about those experiences in interviews.
Why did you hire the last person you hired?
I gave my most recent thumbs up to a developer who knew Django and was willing to continue working with it, but most importantly he could start on-site before the req closed. In large companies, empty seats have expiration dates, and everyone is willing to gamble. Because somebody is better than nobody, and even if they're worse than nobody, then you still get a backfill when they leave or are pushed out. But this developer seems to be working out, but I only helped hire him for another team.
The last engineer I hired onto my team was recruited over the course of two years. I met him at PyCon 2012 and we collaborated on a few open-source projects. Real recruiting can be a long process, not the least of which is due to weird budgeting and bureaucracy. So please don't get frustrated if you're still waiting on an email reply from me! :)
Reduced to a few bullet points, here are the key characteristics:
The other interviewees had some interesting things to say, as well. I recommend checking out the full podcast, now featuring transcripts for everyone, not just me. Thanks again to Michael for having me back!