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Wordsmith how does it work

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Hynek Schlawack 2017-08-18 17:19:11 +02:00
parent 57f3d38e50
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docs/how-does-it-work.rst
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@ -51,7 +51,8 @@ Immutability
In order to give you immutability, ``attrs`` will attach a ``__setattr__`` method to your class that raises a :exc:`attr.exceptions.FrozenInstanceError` whenever anyone tries to set an attribute. In order to give you immutability, ``attrs`` will attach a ``__setattr__`` method to your class that raises a :exc:`attr.exceptions.FrozenInstanceError` whenever anyone tries to set an attribute.
In order to circumvent that ourselves in ``__init__``, ``attrs`` uses (an aggressively cached) :meth:`object.__setattr__` to set your attributes. This is (still) slower than a plain assignment: To circumvent that ourselves in ``__init__``, ``attrs`` uses (an aggressively cached) :meth:`object.__setattr__` to set your attributes.
This is (still) slower than a plain assignment:
.. code-block:: none .. code-block:: none
@ -67,10 +68,10 @@ In order to circumvent that ourselves in ``__init__``, ``attrs`` uses (an aggres
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Median +- std dev: 676 ns +- 16 ns Median +- std dev: 676 ns +- 16 ns
So on my notebook the difference is about 300 nanoseconds (1 second is 1,000,000,000 nanoseconds). So on a standard notebook the difference is about 300 nanoseconds (1 second is 1,000,000,000 nanoseconds).
It's certainly something you'll feel in a hot loop but shouldn't matter in normal code. It's certainly something you'll feel in a hot loop but shouldn't matter in normal code.
Pick what's more important to you. Pick what's more important to you.
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Once constructed, frozen instances differ in no way from regular ones except that you cannot change its attributes. Once constructed, frozen instances don't differ in any way from regular ones except that you cannot change its attributes.