'Requiring only one of two dependencies in a requirements file

Some Python packages require one of two packages as a dependency. For example, Ghost.py requires either PySide or PyQt4.

Is it possible to include such a dependency in a requirements.txt file? Is there any 'or' operator that works with these files?

If not, what can I do to add these requirements to the file so only one of them will be installed?

Solution 1:^[1]

I would use a small Python script to accomplish this

#!/usr/bin/env python
packages = 'p1 p2 p3'.split()

try:
    import optional1
except ImportError: # opt1 not installed 
    try:
        import optional2
    except ImportError: # opt2 not installed
        packages.append('optional2')

print(' '.join(packages))

Have this script executable with

chmod +x requirements.py

And finally run pip with it like this:

pip install $(requirements.py)

The '$(requirements.py)' will execute the requirements.py script and put its output (in this case, a list of packages) into pip install ...

Solution 2:^[2]

For setuptools, you can change the setup code to look similar to here: https://github.com/albumentations-team/albumentations/blob/master/setup.py#L11

Where dependency1 would be installed if none of dependency1 and dependency2 is installed yet, but nothing is installed if any of them is already part of the system.

The caveat is that it doesn't work with wheels, and you need to install with --no-binary to make it work: https://albumentations.ai/docs/getting_started/installation/#note-on-opencv-dependencies

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Solution	Source
Solution 1
Solution 2	Jan RÃ¼egg

'Requiring only one of two dependencies in a requirements file

Solution 1:[1]

Solution 2:[2]

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Related Questions

Solution 1:^[1]

Solution 2:^[2]