I am looking to write something that will display an ordered list of all possible combinations. It can start at something like
11-AA 11-AB 11-AC
...and eventually end at...
59-YZ 59-ZZ
I would also like it if the first part of the number can only be between 1-5. I have been working with itertools, but I am having a hard time generating this specific sort of thing. I can generate all possible combinations of 4 letters repeated twice, but I'm having issues getting the dash in, and telling the program that "Hey, you can only chose between 1 and 4 for the first number".
import itertools
perms = itertools.product('ABCD', repeat=2)
for perm in perms:
print('The possible combinations are', perm)
There is the code for that. This doesn't HAVE to use itertools, that is just what I was familar with.
EDIT: The first answer was precisely what I needed. I didn't like what the itertools was doing because of the commas, but the little snippet you showed me is magic. Thank you.
To answer the question, a loop just seemed less clean? I also just discovered the itertools, and am probably enjoying it too much.
Just do this in equal pieces. One character has to be 1
, 2
, 3
, 4
, or 5
; the second can be any digit; the third must be -
, the last two must be A
, B
, C
, or D
, so:
perms = itertools.product('12345', '0123456789', '-', 'ABCD', 'ABCD')
And then, to join them up into strings:
print('The possible combinations are:')
for perm in perms:
print(''.join(perm))
This starts with 10-AA
, not 11-AA
. There's no way to end with 59
if you start with 11
(assuming you want the numbers in order).
I originally left the -
out and joined up each string with format
, but I think this is slower. It's also at least twice as fast on every Python version I have handy. (The cost of a 1-length loop in C is trivial, as is building a 5-tuple vs. a 4-tuple; the cost of format
vs. join
is not.)
You could also product
up a range(11, 60)
and a product('ABCD', repeat=2)
, then flatten it with chain
, then format
each one. While that's conceptually simpler, it's going to be a lot harder to read, and is about as slow as the flat format
version.
Anyway, in 64-bit python.org 3.3.2 on OS X 10.9:
In [1189]: %timeit collections.deque((''.join(perm) for perm in itertools.product('1234', '1234567890', '-', 'ABCD', 'ABCD')), maxlen=0)
10000 loops, best of 3: 129 µs per loop
In [1190]: %timeit collections.deque(('{}{}-{}{}'.format(*perm) for perm in itertools.product('1234', '1234567890', 'ABCD', 'ABCD')), maxlen=0)
1000 loops, best of 3: 359 µs per loop
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