Earlier quoted context omitted.
Do you have some weird constraint where you can't use 3rd party libraries? Yeah, hash tables aren't built into the language, but libraries to provide them are all over the place. See for example http://fortranwiki.org/fortran/show/Hash+tables . Or you could a C function. Or C++ in some compilers.
I can use them in the sense that I'm allowed to, but the compiler that I use can't compile FLIBS nor most of the libraries in your link; and the ones it could compile, I had to adapt, requiring understanding of what a 'hash table' is beyond just 'it's a key to value mapping'. I didn't want to make my post all about my Fortran problems, but I still think knowing the basics of fundamental data structures is foundationa…
Well, sure knowing the basics of fundamental data structures is foundational knowledge. But you were complaining about lack of hash tables, and it seems what you really had was compiler issues. That's not something unique to Fortran.