如何生成一个序列，其中每个元素至少由六个不同的元素与相同的元素分开

Question

From a list of 8 possible letters I want to generate a random sequence where each element is separated from an identical element by at least six different elements.

sequence_list = []
target_list = ["a","b","c","d","e","f","g","h"]

for i in range(1,41):
    sequence_list.append(random.choice(target_list))
print sequence_list

For example if the first letter in sequence_list is an a it should not be repeated for at least the next 6 items in the list. Same for every other item. Appreciate your help.

Answer 1

this is probably not the most efficient way of doing it, but you can do it like this:

>>> target_list = list(string.ascii_letters[:8])
>>> target_list
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']
>>> sequence_list = []
>>> for i in range(1,41):
...     el_list = [x for x in target_list if x not in sequence_list[-6:]]
...     sequence_list.append(random.choice(el_list))
... 
>>> 
>>> sequence_list
['e', 'h', 'g', 'a', 'c', 'f', 'd', 'b', 'e', 'h', 'g', 'c', 'f', 'd', 'a', 'e', 'b', 'g', 'c', 'f', 'h', 'a', 'e', 'b', 'g', 'd', 'f', 'c', 'h', 'a', 'b', 'g', 'd', 'f', 'e', 'c', 'a', 'b', 'h', 'd']