Greetings,
I am working on a program to produce patterns. What would like is for it to exhaustively produce all possible permutations of a sequence of items but for each permutation produce variations, and also a sort of stutter based on probability / weighted randomess.
Let us say we have tiles of four primary colors: ['Red', 'Blue', 'Green', 'Yellow']. Now we also have 4 alternatives or substitutes for each color ['Maroon', 'Navy_Blue', 'Forest_Green', 'Dark_Brown']
We pick a unique permutation, say: ['Red', 'Blue', 'Yellow', 'Green']
Now I would like to pick the primary colors substitute (say 30% chance for each element) so instead of our plain
['Red', 'Blue', 'Yellow', 'Green']
we might end up with:
['Red', 'Navy_Blue', 'Yellow', 'Forest_Green']
or
['Maroon', 'Navy_Blue', 'Yellow', 'Green']
Whatever... The main point is that sometimes the original color is retained and sometimes the dark color is substituted.
Now I want to take this list and sometimes stutter an element so that there is, let us say a 50% chance for each element, that it is stuttered, and it may be repeated 1 (34%), 2(66%), or 3(33%) times. So that we could get:
['Maroon','Maroon','Navy_Blue', 'Yellow','Yellow','Yellow','Yellow', 'Green']
The program would quit when all 24 (in the case of 4 elements) was exhausted.
Playing around with this:
py> def alt_color(color, color_map=dict(Red='Maroon',
... Blue='Navy_Blue',
... Yellow='Forest_Green',
... Green='Dark_Brown')):
... if random.random() <= 0.3:
... return color_map[color]
... return color
...
py> def reps():
... if random.random() < 0.5:
... return 1
... return random.randint(2, 4)
...
py> def combinations(items, n):
... if n==0:
... yield []
... else:
... for i in xrange(len(items)):
... item_slice = items[i:i+1]
... for c in combinations(items[:i]+items[i+1:], n-1):
... yield item_slice + c
...
py> colors = ['Red', 'Blue', 'Yellow', 'Green']
py> some_colors = combinations(colors, len(colors)).next()
py> some_colors
['Red', 'Blue', 'Yellow', 'Green']
py> alt_colors = [alt_color(c) for c in some_colors]
py> alt_colors
['Red', 'Navy_Blue', 'Yellow', 'Green']
py> rep_colors = [c for color in alt_colors for c in [color]*reps()]
py> rep_colors
['Red', 'Red', 'Navy_Blue', 'Navy_Blue', 'Navy_Blue', 'Yellow', 'Green', 'Green']
Hope some of that is helpful.
Steve -- http://mail.python.org/mailman/listinfo/python-list
