def test_alignment(self):
bwt = BWT(list("banana"))
# bwt.print_table()
string = "ana" # This can be a string, because it supports random access and slicing.
self.assertEqual(bwt.L(string), 3)
self.assertEqual(bwt.U(string), 4)
self.assertEqual(sorted(bwt.get_start_indices(string)), [3,5]) # return is index of last token in match
class MarkovModel:
def __init__(self, string):
self.string = string
self.bwt = BWT(self.string)
def get_n_tokens(self, context, n):
'''
Returns up to n tokens that follow the list of tokens given in context in
the source string, or None if no such tokens exist.
'''
indices = self.bwt.get_start_indices(context)
if indices == []:
return None
index = choice(indices)
return self.get_n_gram_at_index(n, index)
def get_n_gram_at_index(self, n, index):
return self.string[index+1:min(index+1+n ,len(self.string)-1)]
def get_all_possible_n_grams(self, context, n):
indices = self.bwt.get_start_indices(context)
return (self.get_n_gram_at_index(n, index) for index in indices)
