Question

I have an object like this:

t = {'rand_key_1': ['x'], 'rand_key_2': [13,23], 'rand_key_3': [(1)], 'rk5': [1,100,3,4,3,3]}

a dictionary with random keys (string and/or int) which ALL have a list as a value, with varying sizes.

I want to turn this dictionary into an OrderedDict which is ordered depending on the Length of the list of the dictionary items. So after ordering I want to get:

t_ordered = {'rk5': ..., 'rand_key_2': .., 'rand_key_1': .., 'rand_key_3': ..}

(if two or more items have same value, their order do not really matter.

I tried this but I am failing:

OrderedDict(sorted(d, key=lambda t: len(t[1])))

I am not experiences so excuse me if what I try is uber stupid.

What can I do?

Thank you.

Answer 1

You were actually very close with the sorting function you passed to sorted. The thing to note is that sorted will return an interable of the dictionaries keys in order. So if we fix your function to index the dictionary with each key:

>>> sorted(t, key=lambda k: len(t[k]))
['rand_key_3', 'rand_key_1', 'rand_key_2', 'rk5']

You can also specify that the keys are returned in reverse order and iterating directly over these keys:

>>> for sorted_key in sorted(t, key=lambda k: len(t[k]), reverse=True):
...     print sorted_key, t[sorted_key]

rk5 [1, 100, 3, 4, 3, 3]
rand_key_2 [13, 23]
rand_key_3 [1]
rand_key_1 ['x']

Usually you wouldn’t need to create an OrderedDict, as you would just iterate over a new sorted list using the latest dictionary data.