bpo-37158: Simplify and speed-up statistics.fmean() (GH-13832) (GH-13843)
(cherry picked from commit 6c01ebcc0dfc6be22950fabb46bdc10dcb6202c9)
Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com>
diff --git a/Lib/statistics.py b/Lib/statistics.py
index 012845b..5be70e5 100644
--- a/Lib/statistics.py
+++ b/Lib/statistics.py
@@ -320,11 +320,11 @@
except TypeError:
# Handle iterators that do not define __len__().
n = 0
- def count(x):
+ def count(iterable):
nonlocal n
- n += 1
- return x
- total = fsum(map(count, data))
+ for n, x in enumerate(iterable, start=1):
+ yield x
+ total = fsum(count(data))
else:
total = fsum(data)
try:
diff --git a/Misc/NEWS.d/next/Library/2019-06-04-22-25-38.bpo-37158.JKm15S.rst b/Misc/NEWS.d/next/Library/2019-06-04-22-25-38.bpo-37158.JKm15S.rst
new file mode 100644
index 0000000..4a5ec41
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-06-04-22-25-38.bpo-37158.JKm15S.rst
@@ -0,0 +1 @@
+Speed-up statistics.fmean() by switching from a function to a generator.