Fortran language is used in many first-principles matter modeling codes, such as VASP and QE. These codes usually include many files and thousand of lines and are not readable for a newbie. Are there good strategies and resources to master the Fortran language with minimal effort if I have some experience with the PYTHON language? The final purpose is to read and modify the existed Fortran codes such as QE.

Fortran language is used in many first-principles matter modeling codes, such as VASP and QE. These codes usually include many files and thousand of lines and are not readable for a newbie. Are there good strategies and resources to master the Fortran language with minimal effort if I have some experience with the PYTHON language? The final purpose is to read and modify the existing Fortran codes such as QE.