Which language is that? Definitely true that some technologies like SAS and Mathematica have a lot of off-Stack Overflow activity, but curious what you're referring to.

That feature has been added in the last few hours :) https://insights.stackoverflow.com/trends?tags=python%2Cphp%...

I used ggplot2 and gganimate in R. The custom ggplot2 theme is called theme_roboto(): https://github.com/juliasilge/silgelib/blob/master/R/graphin...

That's right: Haskell is disproportionately used in the evenings, but it's not highly used at any time. You can see in the 4th graph that of the 250 languages considered, Haskell is one of the lowest traffic.

This is assuming that SO is a popular destination for Haskell questions.

Github would be the better indicator. Especially if Github could include anonymous stats for private repos too. That would give a good indication about the commercial viability of the various languages.

I'm one of those people who uses Haskell a lot at night time and I rarely use SO for it. I often find answers in documentation, blog posts, IRC, and books. Whereas during my day job I tend to run into a lot of obscure framework errors when I work with Ruby on Rails or the various weird quirks in Javascript where SO is indispensable. I have different kinds of queries with Haskell rather than copy/pasting error msgs, likewise when I use Erlang/Elixir.

Another example is Reddit:

    /r/python 122.1k users
    /r/javascript 82.4k users
    /r/java/ 51.4k users
    /r/php 40.8k users
    /r/cpp 35.7k users
    /r/ruby 31.1k users
    /r/csharp 28.2k users
    /r/haskell 22.8k users
    /r/golang 20.7k users
    /r/c_programming 19.6k users
    /r/swift 17.1k users
    /r/rust 16.1k users
    /r/sql 13.6k users
    /r/scala 10.4k users
    /r/lisp 10.3k users
    /r/clojure 10.0k users

Haskell is not far behind Ruby, C#, or CPP on Reddit. Yet the difference in the SO chart is dramatic.

But no doubt it's not as popular professionally as other languages, sadly, but it's not quite as fringe as this particular data source indicates.

Course author here; I agree about most of the lessons being outdated in the last two years, and that R for Data Science is a great modern source.

I'm working with DataCamp to develop an R course that covers dplyr, tidyr, and other newer additions to the R language.

Good to hear! :)

There are many developers looking for a good job. There are many companies having difficulty finding qualified developers.

Our goal is to solve those problems, and it is not a zero-sum game.

mikk14 is right; the connections were filtered out below a particular threshold (set that threshold too low and everything is connected to everything; set it too high and you miss meaningful connections).

But note that precisely because git/github is used in combination with almost all other tags, it doesn't have a high correlation with any particular technology. A correlation (roughly) means "If I know you use tag X, you're more likely to also use tag Y." But knowing someone uses git doesn't let you guess what other technologies you use, because as you note they can use almost anything.

In short, if you're connected to everything, that means you're correlated with nothing.

It's also the most common language on GitHub in terms of both # of repositories and total pushes: http://githut.info/. Why is it hard to believe?

Perl is indeed quite polarizing (about 30% disliked, a bit more disliked than .NET). It's just not mentioned often enough to show up on the graphs.

It's just a figure of speech, and catchier than 10K.