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Merge pull request #163 from traviscook21/master

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[docs] Fix grammar in purity.rst
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Romain Dorgueil
2017-07-22 11:50:28 +02:00
committed by GitHub
parent 4b441df4f6 dda0a63880
commit 7586502ff1
1 changed files with 4 additions and 4 deletions
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docs/guide/purity.rst
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@ -8,7 +8,7 @@ The major problem we have is that one message (underlying implementation: :class
through more than one component, and at the same time. If you wanna be safe, you tend to :func:`copy.copy()` everything through more than one component, and at the same time. If you wanna be safe, you tend to :func:`copy.copy()` everything
between two calls to two different components, but that's very expensive. between two calls to two different components, but that's very expensive.
Instead of that, we chosed the oposite: copies are never made, and you should not modify in place the inputs of your Instead, we chose the opposite: copies are never made, and you should not modify in place the inputs of your
component before yielding them, and that mostly means that you want to recreate dicts and lists before yielding (or component before yielding them, and that mostly means that you want to recreate dicts and lists before yielding (or
returning) them. Numeric values, strings and tuples being immutable in python, modifying a variable of one of those returning) them. Numeric values, strings and tuples being immutable in python, modifying a variable of one of those
type will already return a different instance. type will already return a different instance.
@ -130,10 +130,10 @@ Now let's see how to do it correctly:
I hear you think «Yeah, but if I create like millions of dicts ...». I hear you think «Yeah, but if I create like millions of dicts ...».
Let's say we chosed the oposite way and copy the dict outside the transformation (in fact, `it's what we did in bonobo's Let's say we chose the opposite way and copied the dict outside the transformation (in fact, `it's what we did in bonobo's
ancestor <https://github.com/rdcli/rdc.etl/blob/dev/rdc/etl/io/__init__.py#L187>`_). This means you will also create the ancestor <https://github.com/rdcli/rdc.etl/blob/dev/rdc/etl/io/__init__.py#L187>`_). This means you will also create the
same number of dicts, the difference is that you won't even notice it. Also, it means that if you want to yield 1 million same number of dicts, the difference is that you won't even notice it. Also, it means that if you want to yield the same
times the same dict, going "pure" makes it efficient (you'll just yield the same object 1 million times) while going "copy dict 1 million times , going "pure" makes it efficient (you'll just yield the same object 1 million times) while going "copy
crazy" will create 1 million objects. crazy" will create 1 million objects.
Using dicts like this will create a lot of dicts, but also free them as soon as all the future components that take this dict Using dicts like this will create a lot of dicts, but also free them as soon as all the future components that take this dict