Join the elements of generators lists

Question

I have two generators lists:

• letters= ('AA', 'AB',...,'AZ) digits= (0,1,2,3,...,9)

From letters and digits, I would like to obtain a third generator list (names) , so that:

• names= ('AA0', 'AA1'.., 'AA9', 'AB0',..'AB9',...'AZ0',...,'AZ9') .

I've tried for a couple of days to achieve 'names' with itertools functions but I cannot achieve the desired result.

The last thing I tried was:

'''
names= dict((key, digits) for key in letters)

def naming():
    for key in names.keys():
        for dig in names.values():
            yield(''.join('{}{}'.format(key, dig)))

names= ('{}{}'.format(key, value) for key, value in names.items())
'''

But it doesn't work, and I definitely want a generator list.

Thank you for your help.

Answer 1

Use itertools.product :

from itertools import product

letters = ("AA", "AB")
digits = (0,9)

["".join(p) for p in product(letters, map(str, digits))]

Output:

['AA0', 'AA9', 'AB0', 'AB9']

Answer 2

What's wrong in this snippet is iterating over names.values() in inner loop.

>>> let=['a','b','c']
>>> dig=[1,2,3]
>>> nms=dict((key, dig) for key in let)
>>> nms
{'a': [1, 2, 3], 'b': [1, 2, 3], 'c': [1, 2, 3]}
>>> nms.values()
dict_values([[1, 2, 3], [1, 2, 3], [1, 2, 3]])

You should rewrite it as

def fn():
 for k in nms.keys():
  for d in nms[k]:
   yield(''.join('{}{}'.format(k,d)))
list(fn())
# ['a1', 'a2', 'a3', 'b1', 'b2', 'b3', 'c1', 'c2', 'c3']