PERF403 update suggestion will make code slower #21890
Description
Summary
Was looking at PERF rules, noticed one of the transformations it suggests will make code like 1.4x slower
import timeit
def main1():
d = {}
for x in range(8):
for i, j in zip(range(x), range(x)):
d[i] = j
def main2():
d = {}
for x in range(8):
d.update({i: j for i, j in zip(range(x), range(x))})
if __name__ == "__main__":
print(timeit.timeit(main1, number=10_000))
print(timeit.timeit(main2, number=10_000))λ python test.py
0.01902620808687061
0.026080582989379764
Version
No response