Nested looping over tuple values in a dictionary with tuple keys python
defaultdict, dictionary, python, tuples
Solution
You'd have to collect all the various key elements into lists, then loop over those (using `itertools.product()`, preferably). The collecting can be done with `zip()`:
from itertools import product
gene_regions, species_plural, ontologies, lengths = zip(*result_dict)
for gene_region, species, ontology, length in product(gene_regions, species_plural, ontologies, lengths):
# do something with this combo.
`product()` produces the same sequence of combinations as if you had nested your loops.
Problem
I have a defaultdict where the key is a 4-tuple (gene_region, species, ontology, length). Looping over it is simple: ``` for gene_region, species, ontology, length in result_dict: ``` However, I'd like to iterate over it in a nested fashion, like this: ``` for gene_region for species for ontology ... ``` How do I do this? Is there no other way than collecting the values first? Or using the following dum-dum way: ``` for gene_region, _, _, _ in result_dict: for _, species, _, _ in result_dict: ... ```