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bpo-41892: Clarify that an example in the ElementTree docs explicitly avoids modifying an XML tree while iterating over it. (GH-22464)
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@ -251,12 +251,18 @@ We can remove elements using :meth:`Element.remove`. Let's say we want to
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remove all countries with a rank higher than 50::
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>>> for country in root.findall('country'):
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... # using root.findall() to avoid removal during traversal
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... rank = int(country.find('rank').text)
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... if rank > 50:
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... root.remove(country)
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...
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>>> tree.write('output.xml')
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Note that concurrent modification while iterating can lead to problems,
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just like when iterating and modifying Python lists or dicts.
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Therefore, the example first collects all matching elements with
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``root.findall()``, and only then iterates over the list of matches.
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Our XML now looks like this:
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.. code-block:: xml
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