Bengt Richter wrote:
> then there's always
>
> if 'x' in d: value = d['x']
> else: value = bsf()
>
> or
>
> try: value = d['x']
> except KeyError: value = bsf()
>
Its worth remembering that the first of those two suggestions is also
faster than using get, so you aren't losing on speed if you write the code
out in full: choose whichever seems clearest and uses the least contorted
code.
(The second is the fastest of all if the value is found, but a lot slower
if the exception gets thrown.)
C:\Python24\Lib>timeit.py -s "d={}" -s "for k in range(1000): d['x%s'%k]=k"
"value = d.get('x45', 'notfound')"
1000000 loops, best of 3: 0.427 usec per loop
C:\Python24\Lib>timeit.py -s "d={}" -s "for k in range(1000): d['x%s'%k]=k"
"value = d.get('z45', 'notfound')"
1000000 loops, best of 3: 0.389 usec per loop
C:\Python24\Lib>timeit.py -s "d={}" -s "for k in range(1000): d['x%s'%k]=k"
"if 'x45' in d: value=d['x45']" "else: value='notfound'"
1000000 loops, best of 3: 0.259 usec per loop
C:\Python24\Lib>timeit.py -s "d={}" -s "for k in range(1000): d['x%s'%k]=k"
"if 'z45' in d: value=d['z45']" "else: value='notfound'"
1000000 loops, best of 3: 0.131 usec per loop
C:\Python24\Lib>timeit.py -s "d={}" -s "for k in range(1000): d['x%s'%k]=k"
"try: value=d['x45']" "except: value='notfound'"
1000000 loops, best of 3: 0.158 usec per loop
C:\Python24\Lib>timeit.py -s "d={}" -s "for k in range(1000): d['x%s'%k]=k"
"try: value=d['z45']" "except: value='notfound'"
100000 loops, best of 3: 2.71 usec per loop
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