On the persistence of bad ideas

A short collection of lessons on how you are not as smart as you think you are

Transcript

1. 1 On the persistence of bad ideas
2. 2 A student def palindrome(s): for i in range(len(s)//2): if s[i] != s[-(i+1)]: return False return True
3. 3 A pythonista def palindrome(s): return all([ s[i] == s[-(i+1)] for i in range(len(s)//2)])
4. 4 A slightly smarter pythonista def palindrome(s): return all(( s[i] == s[-(i+1)] for i in range(len(s)//2)))
5. 5 A fan of lambdas def palindrome(s): return all(map(lambda t: t[0] == t[1], [ (s[i], s[-(i+1)]) for i in range(len(s)//2)]))
6. 6 An Erlang (or Haskell) fan def palindrome(s): if len(s) <= 1: return True elif s[0] == s[-1]: return palindrome(s[1:-1]) else: return False
7. 7 Someone in a hurry from concurrent.futures.thread import ThreadPoolExecutor def palindrome(s): with ThreadPoolExecutor(16) as executor: return all(executor.map( lambda t: t[0] == t[1], [ (s[i], s[-(i+1)]) for i in range(len(s)//2)]))
8. 8 Someone in a hurry (who knows about the GIL) from concurrent.futures.process import ProcessPoolExecutor def equals(t): return t[0] == t[1] def palindrome(s): with ProcessPoolExecutor() as executor: return all(executor.map( equals, [ (s[i], s[-(i+1)]) for i in range(len(s)//2)]))
9. 9 A poet def palindrome(s): return s[::-1] == s
10. 10 A poet who can count def palindrome(s): return s[:len(s)//2:-1] == s[:len(s)//2]
11. 11 What we've just seen • student • pythonistas • lambda fans • functional • threadist • processist • poets
12. 12 Analysis (worst case) 10 100 1000 10000 100000 1000000 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 student pythonista smarter pythonista lamda fan functional threadist processist poet counting poeta
13. 13 http://about.me/rbanffy