[barkingcat]

numpy / scipy both use fortran. Scipy has fortran as a build dependency (ie a large portion of it depends on fortran), and numpy can be built without fortran, but has large portions of optimizations in fortran.

anyone who's ever used numpy/scipy has been using python integrated with fortran.

[ilayn]

Scipy maintainer here. Numpy has no fortran code on itself and uses lapack lite written in C. Scipy has 10% of its codebase with very old F77 libraries that we are removing slowly. Nothing against fortran but this is slowly turning into a urban legend.

The main reason fortran is still used around is fundamentally LAPACK. BLAS has long been converted to C/Assembly, openblas mkl or others. But Lapack is a lot of code to translate not because fortran is better but the original authors wrote it in F77