An interesting Python programming contest ended today. The task was to write the shortest Python module for converting a string of digits to seven-segment display format. The module was to be used like this:
>>> from seven_seg import seven_seg >>> print seven_seg('0123456789') _ _ _ _ _ _ _ _ | | | _| _||_||_ |_ ||_||_| |_| ||_ _| | _||_| ||_| _|
Solutions were measured with the Unix command wc -c seven_seg.py.
The shortest solution (by André Roberge, who is apparenly some kind of a genius) is 117 characters long. My best try was this 120-character-long one-liner of obfuscated Python:
seven_seg=lambda i,j=''.join:j(j(' _ _|_|_ | |'[ord('f\xda($\xbaDFZ64'[int(d)])>>r&14:][:3]for d in i)+'\n'for r in[6,3,0])
(Replace \xda and \xba with actual 8-bit characters, and make sure the file has no trailing newline to get a 120-byte long file.)
There is also a 30-character-long cheat that fools the test suite into thinking it is a valid solution:
class seven_seg(str):__eq__=id
It was fun to read about various solutions by other people in this thread on comp.lang.python, and in other places.
Update: Read André's Deconstruction of the 117-character solution (with insightful readers' comments about the Chinese Remainder Theorem).
