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.
I have code that makes weighted randomness. I have code that makes permutations, but I am having trouble putting this all together... While i work on it though that i might ask for help... I'd like for the code to be reusable and am building a library of functions for patterns.
If you had a randomizeList function and a stutterList function then your top-level function would look like this:
permutations = permute(['Red', 'Blue', 'Yellow', 'Green']) permutations = [ randomizeList(list) for list in permutations ] permutations = [ stutterList(list) for list in permutations ]
In other words you start with the basic permutations, then apply the randomize function to each permutation, then apply the stutter function.
The randomizeList function should walk through the list, find the right randomize list for that list element (a dict could help with that - look up the list element and get the randomize list), and build a new list with the randomized values.
The stutterList function walks through the list building a new list with possibly repeated elements.
HTH, Kent
cheers, kevin
### This is not mine, it is from a python book... I believe the Lutz book
def permute(list):
if not list: # shuffle any sequence
return [list] # empty sequence
else:
res = []
for i in range(len(list)):
rest = list[:i] + list[i+1:] # delete current node
for x in permute(rest): # permute the others
res.append(list[i:i+1] + x) # add node at front
return res
mport random
### This this is mine, but seems to work anyway hee hee
def windex(lst):
'''an attempt to make a random.choose() function that makes weighted choices
accepts a list of tuples with the item and probability as a pair like: >>> x = [('one', 0.25), ('two', 0.25), ('three', 0.5)] >>> y=windex(x)''' n = random.uniform(0, 1) for item, weight in lst: if n < weight: break n = n - weight return item
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