如何从具有列表值的字典中获取一系列键来检索所有可能的组合

Question

I have for instance this dictionary

d={'M':['ATG'],'D':['GAC','GAT'],'E':['GAA','GAG']}

What I'd like to have as an output given a sequence of keys is a list with all possible sequences. (could be a string as well, in which all the possible sequences would be in separate lines "\\n")

sequence = "MDE" 

So, the output should be the following:

['ATGGACGAA','ATGGACGAG','ATGGATGAA','ATGGATGAG']

What I've tried so far is the following, but of course it's not what I want:

seq_trans = ''

for aa in sequence:
  for k, v in d.iteritems():
    if k == aa:
      for item in v:
        seq_trans= seq_trans + item
print seq_trans

And what I get for "MDE" is:

'ATGGACGATGAAGAG'

Answer 1

You can use itertools.product here, it returns Cartesian product of the input iterables.

In [78]: seq="MED"

In [79]: ["".join(x) for x in product(*(d[y] for y in seq))]
Out[79]: ['ATGGAAGAC', 'ATGGAAGAT', 'ATGGAGGAC', 'ATGGAGGAT']