How to iterate a YAML file to give all possible combinations from items in different lists in PYTHON

Question

I have a YAML document with sequences like this

---
One: 
 - a
 - b
 - c
Two:
 - d
 - e
Three:
 - f
 - g
 - h 
 - i

I need to get all possible combinations of the elements taken from each list one at a time, only one element at every instance from the list and all list must be used.

I need to do this is python.

Until now, I can print the YAML file using:

#!/usr/bin/env python

import yaml

with open("parameters.yaml", 'r') as stream:
    try:
        print(yaml.load(stream))
    except yaml.YAMLError as exc:
        print(exc)

Answer 1

A solution using itertools:

import itertools
import yaml

with open('parameters.yaml', 'r') as stream:
    try:
        inputdict = yaml.safe_load(stream)
    except yaml.YAMLError as exc:
        print(exc)

total_list = [inputdict[key] for key in inputdict]
combinations = list(itertools.product(*total_list))
print(combinations)

Output:

[('a', 'd', 'f'), ('a', 'd', 'g'), ('a', 'd', 'h'), ('a', 'd', 'i'), ('a', 'e', 'f'), ('a', 'e', 'g'), ('a', 'e', 'h'), ('a', 'e', 'i'), ('b', 'd', 'f'), ('b', 'd', 'g'), ('b', 'd', 'h'), ('b', 'd', 'i'), ('b', 'e', 'f'), ('b', 'e', 'g'), ('b', 'e', 'h'), ('b', 'e', 'i'), ('c', 'd', 'f'), ('c', 'd', 'g'), ('c', 'd', 'h'), ('c', 'd', 'i'), ('c', 'e', 'f'), ('c', 'e', 'g'), ('c', 'e', 'h'), ('c', 'e', 'i')]