I spent three months this year in the Winter 2013 batch of [Hacker School][]. Below are some thoughts on what it did for me, excerpted from my feedback to the organization.
Hacker School gave me a critical mass of people with whom I could interact, having coding as the context of interaction. I have never had that before.
The single most important outcome of this experience was my acculturation as a programmer. I learned best practices, terms (both standard and jargon), the names of companies and services, and more generally how to think and express myself within this culture. For the first time I came to think of myself as a programmer. I was so keyed up during the batch that I slept about five hours a night, and I dreamt of coding on most nights whose visions I can remember.
I have some sense now of the dimensions of the mind-space in which the life of a coder is situated, as though I have become aware the height of the unseen vaults overhead when I stand in a dark cathedral.
The community has provided me many models for how to do things and how to conduct myself as a programmer. I finally overcame the sloth that had previously kept me from learning how to use Git and VirtualEnv, and those things have led to better workflow hygiene all around — it has led me to pay much more attention to my Python and Ubuntu installations, for instance. I finally remembered to begin making regular use of list and dictionary comprehensions in my code, too.
Hacker School has provided far more chances for me to receive fruitful criticism (Karl Popper's phrase) than I have ever gotten before on my code or my thinking. The community is a sort of personal Stack Overflow, without the insults or grubbing for votes, and that has been very helpful. The use of [the internal chat client] Humbug [now renamed Zulip, 20130813] greatly facilitated communication, including after the batch, and think life would have been much harder if we had been limited to IRC or Skype chat.
Other specific gains I'm aware of are, if not speed, then anyway "motor memory" as it affects my proficiency with coding syntax and my choice of tools. I have a long way to go yet but my progress these three months has been greater than at any other time in my life as a coder. I have become comfortable with SQLite3, BeautifulSoup4, Feedparser, and NLTK, and am much more willing now to pick up a module I don't know and try to learn how to use it. Now that the batch has been over for three weeks and I am back to the insanity of my philological work — using chopsticks to clear a room of swarms of gnats is what it's like — I constantly find myself envisioning efficiencies and then building them or hunting for tools rather than letting myself get into a rut doing things the same way as before. That shows me that the grooves of my mind have indeed been altered substantively by my experience these three months. I do not feel quite right if several days go by without coding, either — I am still making peace with that, as though after a religious experience that demands changes in how I live.