I lost nearly all my modules installing 3.7

[dieter]

Elliott Roper <nospam at yrl.co.uk> writes:
> ...
> install scipy wrote an error message longer than War and Peace that finished 
> with:-
> ____________________________________________________________________________
> error: library dfftpack has Fortran sources but no Fortran compiler found

An error message of the type I like: precise:
Install a "Fortran compiler" and try again.

> ...
> and matplotlib produced a beautifully formatted report that started with:
> __________________
> Complete output from command python setup.py egg_info:
> IMPORTANT WARNING:

This is a warning only (even though it is marked as important).

> pkg-config is not installed.
> matplotlib may not be able to find some of its dependencies

And the warning message is precise again: install "pkg-config"
to get rid of it.

I do not know "pkg-config". The name seems to indicate an
operating system package; but, it might also be a Python extension
package (less likely).
I would start with the "matplotlib"
installation instructions to look for information about it.