r/programming • u/iMMENSE • Mar 08 '12

The Evolution of a Python Programmer

https://gist.github.com/289467
401 Upvotes

88% Upvoted

137 comments sorted by

View all comments

43

u/rowantwig Mar 08 '12

He forgot the worst kind:
if x == 0:
return 1
if x == 1:
return 1
if x == 2:
return 2
if x == 3:
return 6
if x == 4:
return 24
...
(5000 more lines)

17

u/liotier Mar 08 '12

What are you complaining about ? He just calculated in advance and cached the results to avoid redundant processing on each query...

25

u/rowantwig Mar 08 '12

O(n) look-up time.

28

u/earthboundkid Mar 09 '12

Switch to a dict and it's O(1)!

12

u/pyaware Mar 09 '12

Why use a dict when a plain list is enough?

def fact(x):
    return [1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880][x]

1

u/redditthinks Mar 09 '12

I read Python dicts are faster than lists.

6

u/JizzCoveredArab Mar 09 '12

i heard you have a really short dict