'None' is not displayed as I expected in Python interactive mode

Question

I thought the display in Python interactive mode was always equivalent to print(repr()), but this is not so for None. Is this a language feature or

Answer 1

It's a deliberate feature. If the python code you run evaluates to exactly None then it is not displayed.

This is useful a lot of the time. For example, calling a function with a side effect may be useful, and such functions actually return None but you don't usually want to see the result.

For example, calling print() returns None, but you don't usually want to see it:

>>> print("hello")
hello
>>> y = print("hello")
hello
>>> y
>>> print(y)
None