Advantages of Default Factory in Dataclasses
Paul Bryan
pbryan at anode.ca
Tue Nov 16 10:17:26 EST 2021
On Tue, 2021-11-16 at 17:04 +0400, Abdur-Rahmaan Janhangeer wrote:
> A simple question: why do we need field(default_factory ) in
> dataclasses?
To initialize a default value when a new instance of the dataclass is
created. For example, if you want a field to default to a dict. A new
dict is created for each instance of the dataclass created.
> Why not make that field as an attribute return a function?
I do not understand the question.
> Useful implementation examples / use cases appreciated.
Any case where a you want a dataclass field to default to a mutable
value. Examples: dicts, lists, other dataclasses.
Paul
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