It depends on what aspect of programming you want to network over.

If you want too discuss the intricacies of different algorithms and nerd out over O notation timings and such then you’ll want to inhabit very different spaces then if you want to write videogames which is a different space from if you want to make home automation gadgets and small webpages.

Sure they’re all “programming” but you’ll generally find the people doing them in different spots.

Overall though, broad ways:

• Hackaday.com has a decent community and events
• Hackerspaces will sometimes have networking events
• local college classes
• events at local college
• mentor first robotics team (they often need programming mentors too)
• Make stuff and blog about it

I’ll say though, networking with other programmers isn’t how you get good at programming in my experience (currently as a Senior Software Engineer developing programs for language learning). In my experience being curious and trying to make stuff is how you get good. That billionaire quote only really truly applies to money.