[BoumTAC]

Don't you think `x["foo"] == 5` but `x.foo == 4` is a hell of a lot confusing ?

Don't you think it should not be possible to have such a thing ? To me it's so prone to error and there is absolutely too much gain to fix this.

[dragonwriter]

> Don't you think `x["foo"] == 5` but `x.foo == 4` is a hell of a lot confusing ?

No, having used lots of OO languages before JS and its “objects are dictionaries are arrays and member access and string indexing and integer indexing are all equivalent and can be used interchangeably, except you can't use member access where the key isn't a valid identifier” approach, which I find more confusing and error prone (though I’ve since had to use JS enough to be proficient in that, too.)

Indexing an object as an indexable collection and accessing a member (field, property, or method) of the object are fundamentally different things, and having a collection item with a particular string index isn’t the same thing as an object member with a similar identifier name.

This use of objects as also quasi-associative-arrays is so broken that JS’s actual associative-array type (Map) can’t use indexing notation because of it, and has to use .get() and .set() instead, unlike the associative array types of most other dynamic languages (and several statically-typed OO languages).

The JS way is less bad as a type-specific behavior (e.g., Ruby ActiveSupport’s HashWithIndifferentAccess), though.

[klyrs]

> Don't you think `x["foo"] == 5` but `x.foo == 4` is a hell of a lot confusing ?

No. They're different notations; one means `x.__getitem__('foo')` and the other means `x.__getattribute__('foo')`. Why should they be the same? It isn't confusing that `5-4 == 1` but `5+4 == 9`, after all.

If we assume that the dict class was enhanced with your proposed equivalence, would you want `d['items']` to be the function `d.items`? Would that not make 'items' a forbidden key?

[execveat]

No, there is no confusion here at all (for a Python developer). I would consider it a code smell though as the whole problem is completely avoidable by better naming.

By the way, there is a vulnerability (Prototype Pollution) that is only possible due to this behaviour in JS: https://portswigger.net/web-security/prototype-pollution

[klibertp]

You can't confuse keys in a hash table with properties of objects. It's not confusing, it's a useful distinction.

Most languages that have both objects and associative arrays (so not Lua or JavaScript) make this distinction.

It's not particularly error prone. You're simply refusing ("don't care why") to learn how to use the tool you're given.

[BoumTAC]

user dictionnary => user["email"]

user instance from a django model => user.email

It is error prone. You're simply refusing to see an aberration.

That's how the language works, but it doesn't mean it's intuitive and easy to understand especially for a language known for being easy to use and understand.

[pedvide]

In pandas for example that can happen often: `df["count"] == 5` and `df.count == 5` are logically different expressions that will give different answers

[lozenge]

So how can d.update() coexist with d["update"]? Updating a dictionary vs examining a dictionary that has a key "update"?

[PinkRidingHood]

Try This:

  x = {"users": [12,21,54], "items": [1,2,3]}  # group owned items
  >>> x["items"]
  [1,2,3]
  >>> x.items
  <built-in method items of dict object at 0x00>