A Python module and command line tool for parsing Fortran namelist files
The documentation for f90nml is available from Read The Docs.
http://f90nml.readthedocs.org/en/latest/
f90nml is a Python module and command line tool that provides a simple
interface for the reading, writing, and modifying Fortran namelist files.
A namelist file is parsed and converted into a Namelist object, which
behaves like a Python dict. Values are converted from Fortran data types
to equivalent primitive Python types.
The command line tool f90nml can be used to modify individual values inside
of a shell environment. It can also be used to convert the data between
namelists and other configuration formats. JSON and YAML formats are currently
supported.
To read a namelist file sample.nml which contains the following namelists:
&config_nml
input = 'wind.nc'
steps = 864
layout = 8, 16
visc = 1.0e-4
use_biharmonic = .false.
/we would use the following script:
import f90nml
nml = f90nml.read('sample.nml')which would would point nml to the following dict:
nml = {
'config_nml': {
'input': 'wind.nc',
'steps': 864,
'layout': [8, 16],
'visc': 0.0001,
'use_biharmonic': False
}
}File objects can also be used as inputs:
with open('sample.nml') as nml_file:
nml = f90nml.read(nml_file)To modify one of the values, say steps, and save the output, manipulate the
nml contents and write to disk using the write function:
nml['config_nml']['steps'] = 432
nml.write('new_sample.nml')Namelists can also be saved to file objects:
with open('target.nml') as nml_file:
nml.write(nml_file)To modify a namelist but preserve its comments and formatting, create a
namelist patch and apply it to a target file using the patch function:
patch_nml = {'config_nml': {'visc': 1e-6}}
f90nml.patch('sample.nml', patch_nml, 'new_sample.nml')A command line tool is provided to manipulate namelist files within the shell:
$ f90nml config.nml -g config_nml -v steps=432&config_nml
input = 'wind.nc'
steps = 432
layout = 8, 16
visc = 1.0e-4
use_biharmonic = .false.
/See the documentation for details.
f90nml is available on PyPI and can be installed via pip:
$ pip install f90nml
The latest version of f90nml can be installed from source:
$ git clone https://github.com/marshallward/f90nml.git $ cd f90nml $ pip install .
There is a conda-forge feedstock (not maintained, nor supported by, the Author).
Information on supported versions and platforms, and detailed installation instructions
using conda and conda-forge is available here:
https://github.com/conda-forge/f90nml-feedstock
but TL;DR:
$ conda install -c conda-forge f90nml
f90nml is not distributed through any official packaging tools, but it is
available on Arch Linux via the AUR:
$ git clone https://aur.archlinux.org/python-f90nml.git $ cd python-f90nml $ makepkg -sri
Volunteers are welcome to submit and maintain f90nml on other
distributions.
Users without install privileges can append the --user flag to pip from
the top f90nml directory:
$ pip install --user .
If pip is not available, then setup.py can still be used:
$ python setup.py install --user
When using setup.py locally, some users have reported that --prefix=
may need to be appended to the command:
$ python setup.py install --user --prefix=
The command line tool offers support for conversion between namelists and YAML
formatted output. If PyYAML is already installed, then no other steps are
required. To require YAML support, install the yaml extras package:
$ pip install f90nml[yaml]
To install as a user:
$ pip install --user .[yaml]
Users are welcome to submit bug reports, feature requests, and code contributions to this project through GitHub. More information is available in the Contributing guidelines.