Terry J. Reedy <[email protected]> added the comment:
Bound is created with 5 public attributes:
>>> dir(bound)
[..., 'apply_defaults', 'args', 'arguments', 'kwargs', 'signature']
>>> bound.args
()
>>> bound.arguments
{}
>>> bound.kwargs
{}
msg376578: I don't understand 'non-existent' arguments, Nor 'what
happened...print... ignored' as there is no previous print.
msg376590: Given " Changes in arguments will reflect in args and kwargs.", I
agree that changes to 'arguments' *apparently* not being reflected in 'args'
and 'kwargs' is initally a bit puzzling
.
>>> bound.kwargs == bound.arguments
True
>>> bound.arguments['something'] = 'guess'
>>> bound.kwargs
{}
>>> bound.arguments
{'something': 'guess'}
However, your 'two' function takes no arguments, so valid values of args and
kwargs must be empty for them to be used in a call. In all cases, args() and
kwargs() must look at the signature to see which key-value pairs they should
extract from arguments.
>>> def f(a): pass
>>> signature(f).bind() # Must pass value arguments
Traceback (most recent call last):
...
TypeError: missing a required argument: 'a'
>>> b = signature(f).bind(3)
>>> b.arguments
{'a': 3}
>>> b.args
(3,) # Because 'a' is positional.
>>> b.kwargs
{} # Because 'a' is not keyword only.
>>> b.arguments['a']=5
>>> b.args
(5,) # Legitimate change reflected here.
Perhaps the doc could be improved, but I have no particular suggestion.
----------
assignee: -> docs@python
components: +Documentation -Library (Lib)
nosy: +docs@python, terry.reedy
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<https://bugs.python.org/issue41745>
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