What does the '[notebook]' in 'pip install ipython[notebook]' mean?
问题 The '[notebook]' appears to be some kind of modifier, but as I was installing Jupyter rather than ipython I suddenly wondered what other variants of this modifier I've been missing out on, perhaps something that would install specific kernels or configurations for me. Unfortunately, I don't know what the '[notebook]' is: pip search '[notebook]' finds nothing, and I don't know what this modifier is or is called. I've looked at the PyPI naming convention pep, etc, but I couldn't find anything