@serhiy-storchaka, do you have suggestions here?

I understand the use of set comprehension instead of generator, it can add a tiny speed up. But why get rid of unpack?

I wanted to make the code more readable. But I'll revert it as it's slower:

deftest1(paths):sep='/'try:isabs,= {p.startswith(sep)forpinpaths}exceptValueError:raiseValueError("Can't mix absolute and relative paths")fromNoneprefix=sepifisabselsesep[:0]returnprefixdeftest2(paths):sep='/'iflen({p.startswith(sep)forpinpaths})!=1:raiseValueError("Can't mix absolute and relative paths")prefix=sepifpaths[0].startswith(sep)elsesep[:0]returnprefix

wannes@Stefans-iMac Desktop % python -m timeit -s"import test""test.test1(['foo'])"&& python -m timeit -s"import test""test.test2(['foo'])"1000000 loops, best of 5: 369 nsec per loop# unpack500000 loops, best of 5: 451 nsec per loop# no unpack# -> 1.22x slower

@erlend-aasland, do you think this can be merged now? I addressed serhiy-storchaka's question.

@erlend-aasland, do you think this can be merged now? I addressed serhiy-storchaka's question.

I'll run PGO benchmarks for the updated PR first.

UPDATE: I'm getting between 5% and 20% speedups, similar to the speedup in the PR description.

@erlend-aasland, could you merge it? It has been approved by serhiy.

@nineteendo: yes, it was on my list; there is no need for the extra ping. There is no hurry; I'll land it tomorrow morning. Please avoid unneeded pings.

Thanks.

Please avoid unneeded pings.

Sorry, sometimes I get no response, and then I don't know if my message was even read.