https://github.com/python/cpython/commit/d5e9aa690a190bcfa9b43cd3858e26b7b2f72d4f
commit: d5e9aa690a190bcfa9b43cd3858e26b7b2f72d4f
branch: main
author: Bénédikt Tran <[email protected]>
committer: picnixz <[email protected]>
date: 2025-01-18T11:45:18+01:00
summary:
gh-118761: Improve import time for `csv` (#128858)
This reduces the import time of the `csv` module by up to five times,
by importing `re` on demand.
In particular, the `re` module is no more implicitly exposed as `csv.re`.
files:
A Misc/NEWS.d/next/Library/2025-01-15-09-45-43.gh-issue-118761.TvAC8E.rst
M Lib/csv.py
diff --git a/Lib/csv.py b/Lib/csv.py
index cd202659873811..0a627ba7a512fa 100644
--- a/Lib/csv.py
+++ b/Lib/csv.py
@@ -63,7 +63,6 @@ class excel:
written as two quotes
"""
-import re
import types
from _csv import Error, writer, reader, register_dialect, \
unregister_dialect, get_dialect, list_dialects, \
@@ -281,6 +280,7 @@ def _guess_quote_and_delimiter(self, data, delimiters):
If there is no quotechar the delimiter can't be determined
this way.
"""
+ import re
matches = []
for restr in (r'(?P<delim>[^\w\n"\'])(?P<space>
?)(?P<quote>["\']).*?(?P=quote)(?P=delim)', # ,".*?",
diff --git
a/Misc/NEWS.d/next/Library/2025-01-15-09-45-43.gh-issue-118761.TvAC8E.rst
b/Misc/NEWS.d/next/Library/2025-01-15-09-45-43.gh-issue-118761.TvAC8E.rst
new file mode 100644
index 00000000000000..38d18b7f4ca05e
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-01-15-09-45-43.gh-issue-118761.TvAC8E.rst
@@ -0,0 +1,3 @@
+Reduce the import time of :mod:`csv` by up to five times, by importing
+:mod:`re` on demand. In particular, ``re`` is no more implicitly exposed
+as ``csv.re``. Patch by Bénédikt Tran.
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