#20989: tuple() and dict() accept iterators
---------------------------------+--------------------
Reporter: jeroen.pulles@… | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: master
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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As I understand it, dict() and tuple() accept iterators, e.g.
{{{
l = [1, 2, 3]
tuple(v for v in l)
}}}
There are various calls to tuple() that place the iterator in a list
comprehension before feeding the list to tuple(). For example in
django/db/models/sql/query.py:
{{{
aliases = tuple([change_map.get(a, a) for a in aliases])
}}}
can be written as:
{{{
aliases = tuple(change_map.get(a, a) for a in aliases)
}}}
saving two characters, an extra iteration and list creation. The same goes
for dict(), where dict([(v, v) for v in l]) can be rewritten as dict((v,
v) for v in l).
----
A shell command like this can replace the calls. When I tried it, I got
lots of errors in the unit tests, but my impression was that that didn't
have anything to do with the edit...
{{{
find django/ -name '*.py' -print0 \
| xargs -n 200 -0 grep -l 'tuple([[][^]]\+[]])' \
| while read F
do
cp "$F" "$F.orig"
sed -e 's/tuple([[]\(.*\)[]])/tuple(\1)/' "$F.orig" > "$F"
done
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/20989>
Django <https://code.djangoproject.com/>
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