哪个是python中更好更快的方法？

Question

Which way is faster in python?

if status=='Failed' or status=='Terminated' or status=='Aborted' or status=='Expired':
   break

or

if status in ['Failed', 'Terminated', 'Aborted', 'Expired']:
   break

Answer 1

The second one is slightly faster if you tend to fail the comparison in the first/second entry. That's likely because the CONTAINS_OP is a single bytecode operation and goes into mostly-native code for iterating the list. The first solution is checking each comparison in pure python which has some unnecessary overhead.

But the difference is trivial and the overall time is usually ~0.3 μs per the whole check on my system, so it either shouldn't matter in practice, or the code should not use Python in the first place.

You should test questions like that yourself. You can wrap your code in time checks:

def first(rep):
    status='foobar'
    for x in range(rep):
        if status=='Failed' or status=='Terminated' or status=='Aborted' or status=='Expired':
            pass

rep = 1000000
start = time.perf_counter()
first(rep)
diff1 = time.perf_counter()-start

and compare the results.