I have a dictionary:
d = {"A":{"a":1, "b":2, "c":3}, "B":{"a":5, "b":6, "c":7}, "C":{"a":4, "b":6, "c":7}}
I want to sort the keys "A", "B" and "C" in a list, first on the basis of numerical values of "a", then if some tie occurs on the basis of numerical values of "b" and so on.
How can I do it?
You can use:
sorted(d, key=lambda key:(d[key]['a'], d[key]['b'], d[key]['c']))
And here is a general solution in case you have an arbitrary number of elements in the inner dictionaries:
sorted(d, key=lambda key:[value for value in sorted(d[key].items())])
>>> d = {"A":{"a":1, "b":2, "c":3}, "B":{"a":5, "b":6, "c":7}, "C":{"a":4, "b":6, "c":7}}
>>>
>>> d.items()
[('A', {'a': 1, 'c': 3, 'b': 2}), ('C', {'a': 4, 'c': 7, 'b': 6}), ('B', {'a': 5, 'c': 7, 'b': 6})]
>>> sorted(d.items(), key=lambda x: [y[1] for y in sorted(x[1].items())])
[('A', {'a': 1, 'c': 3, 'b': 2}), ('C', {'a': 4, 'c': 7, 'b': 6}), ('B', {'a': 5, 'c': 7, 'b': 6})]
Make a list of your dictionary like so:
my_list = [(key, value) for item in d.items()]
Then sort the list using whatever criteria you have in mind:
def sort_function(a, b):
# whatever complicated sort function you like
return True if a > b else False
my_list.sort(sort_function)
