Andy Andy - 4 months ago 33
Python Question

Sort dictionary of dictionaries by value

I have this dictionary:

statuses = {
'pending' : {'status_for':'all', 'position':1},
'cancelled' : {'status_for':'all','position':2},
'approved' : {'status_for':'owner', 'position':1},
'rejected - owner' : {'status_for':'owner', 'position':2},
'accepted' : {'status_for':'dev', 'position':1},
'rejected - developer' : {'status_for':'dev', 'position':3},
'closed' : {'status_for':'dev', 'position':5},
}


I've also got a function to pull all
status_for
values of either
owner
or
dev
that looks like this and put it into a PyQt QComboBox:

for s in statuses:
if statuses[s]['status_for'] == "dev" or statuses[s]['status_for'] == "all":
cb_developer_status.addItem(s.capitalize(), s)


I'd like to order these by the
position
value though. What is a good way to do this, so that when I populate by combobox I have it in a predefined order?

I realize that the snippet above is checking for both 'dev' and 'all', my assumption right now is that I'd have to loop through the dictionary twice to get the two separate blocks in the order I wish (ie. 'all' appears before 'dev').

I saw this post, but I'm not sure how to convert this answer to something that
is a dictionary of dictionaries.

Answer

Would something like this work? Similar to the post you linked, this uses the key function of sorted to provide a custom sort order. iteritems() returns a (key, value) tuple, so that gets passed into lambda (x, y): y['position'], where y['position'] is the value (your nested dictionary, keyed by the status), and position is the item by which you want to sort.

In [35]: statuses = {
            'pending' : {'status_for':'all', 'position':1},
            'cancelled' : {'status_for':'all','position':2},
            'approved' : {'status_for':'owner', 'position':1},
            'rejected - owner' : {'status_for':'owner', 'position':2},
            'accepted' : {'status_for':'dev', 'position':1},
            'rejected - developer' : {'status_for':'dev', 'position':3},
            'closed' : {'status_for':'dev', 'position':5},
            }

In [44]: for s in sorted(statuses.iteritems(), key=lambda (x, y): y['position']):
   ....:     print s
   ....:
   ....:
('accepted', {'position': 1, 'status_for': 'dev'})
('approved', {'position': 1, 'status_for': 'owner'})
('pending', {'position': 1, 'status_for': 'all'})
('rejected - owner', {'position': 2, 'status_for': 'owner'})
('cancelled', {'position': 2, 'status_for': 'all'})
('rejected - developer', {'position': 3, 'status_for': 'dev'})
('closed', {'position': 5, 'status_for': 'dev'})
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