Sorting a list of dictionaries in a given arbitrary order

Question

I have a list of Dictionaries. Say

[{'name':'Homer', 'age':39, 'desg':'A'}, {'name':'Bart', 'age':10, 'desg':'A'},
{'name':'Lucy', 'age':27, 'desg':'C'}, {'name':'John', 'age':18, 'desg':'B'},
{'name':'Aryan', 'age':20, 'desg':'C'}]

I want to sort this list with desg in order of A,C,B.

I can sort it in A,B,C by sorted(list, lambda x: x['desg']) and reverse by using reverse=True flag, but unable to sort it in the above mentioned pattern.

Answer 1

First, define the order of your keys:

order = {'A':0, 'B':2, 'C':1}

Now, sort in that order:

sorted(l, key=lambda x:order[x['desg']])
#[{'name': 'Homer', 'age': 39, 'desg': 'A'}, 
# {'name': 'Bart', 'age': 10, 'desg': 'A'}, 
# {'name': 'Lucy', 'age': 27, 'desg': 'C'}, 
# {'name': 'Aryan', 'age': 20, 'desg': 'C'}, 
# {'name': 'John', 'age': 18, 'desg': 'B'}]