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gh-84522: Add for-loop to apply-method-to-sequence FAQ (#94660)

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Samuel Sloniker 2022-11-10 20:16:16 -08:00 committed by GitHub
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Doc/faq/programming.rst
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@ -1279,13 +1279,25 @@ Or, you can use an extension that provides a matrix datatype; `NumPy
<https://numpy.org/>`_ is the best known. <https://numpy.org/>`_ is the best known.
How do I apply a method to a sequence of objects? How do I apply a method or function to a sequence of objects?
------------------------------------------------- -------------------------------------------------------------
Use a list comprehension:: To call a method or function and accumulate the return values is a list,
a :term:`list comprehension` is an elegant solution::
result = [obj.method() for obj in mylist] result = [obj.method() for obj in mylist]
result = [function(obj) for obj in mylist]
To just run the method or function without saving the return values,
a plain :keyword:`for` loop will suffice::
for obj in mylist:
obj.method()
for obj in mylist:
function(obj)
.. _faq-augmented-assignment-tuple-error: .. _faq-augmented-assignment-tuple-error:
Why does a_tuple[i] += ['item'] raise an exception when the addition works? Why does a_tuple[i] += ['item'] raise an exception when the addition works?