Python overtakes JavaScript as most questioned language on StackOverflow

Re:Python overtakes JavaScript as most questioned language o... by marcianx on Saturday April 20, 2019 @10:56AM (#19706830)

I don't think mutability is a concern if your goal is to get a bidi map between strings and (mutable) _instances_; i.e. if you just want to use the reference to the dict itself as the hash rather than the contents of the dict itself.

[ Parent | on HN ]

Re:Python overtakes JavaScript as most questioned language o... by BurningFrog on Saturday April 20, 2019 @11:39AM (#19707089)

Yeah, I don't actually know if Python computes hashes for dicts by content or "identity".

I just assumed it was the former, based on the fact that dicts are disallowed as keys.

[ Parent | on HN ]

Re:Python overtakes JavaScript as most questioned language o... by fiddlerwoaroof on Saturday April 20, 2019 @01:26PM (#19707689)

It’s been a while, but I’m pretty sure the reason why a dictionary can’t have a dictionary as it’s key is because the dictionary class doesn’t implement the __hash__ method that would compute the hashcode.

[ Parent | on HN ]

Re:Python overtakes JavaScript as most questioned language o... by np_tedious on Sunday April 21, 2019 @06:34AM (#19711464)

This is definitely the proximate reason.

The reason for that choice is because the object is mutable.

[ Parent | on HN ]

Re:Python overtakes JavaScript as most questioned language o... by fiddlerwoaroof on Sunday April 21, 2019 @02:39PM (#19713724)

Sure, but as others have mentioned, you can make your own choice by subclassing dict and defining your own hash function, as long as that function is defined in a way that follows the appropriate rules.

[ Parent | on HN ]