This is trivial but sometimes misleading.
>>> 1 1 >>> 2 2 >>> 'Foo' 'Foo' >>> None # Nothing displayed on the next line >>> b = None >>> b # Nothing displayed on the next line
Most misleading when a generator yields a
None–it does yield something, just not displayed:
>>> def gen_none(): ... yield None ... >>> g = gen_none() >>> next(g) >>> # Did it yield a value?
>>> str(None) 'None' >>> repr(None) 'None' >>> print(None) None
Jupyter notebooks behave the same way. See Stack Overflow: Display None values in IPython。