[scikit-learn] make all new parameters keyword-only?

[Andreas Mueller]

On 11/14/18 8:36 PM, Hanmin Qin wrote:
> I agree that this feature is advantageous and I'm +1 to apply it to 
> new classes/functions, but for existing classes/functions, does it 
> seem strange that only certain arguments are keyword only (i.e., some 
> arguments can be specified by position, while others can't)?
>
yes, but it would discourage users from specifying any by position, 
which I think they really shouldn't.

No-one understands what RandomForestClassifier(100, gini, 5, 6, 7, .3, 
.4, 3, .1, .2, True)  means.

And if we deprecate a parameter it might still run but mean something else.