I use Python all the time for quick little scripting tasks.  There’s nothing better to slice and dice a file, so I use Python for a lot of reporting tasks.  That usually involves building some kind of data structure in my script that I’m slicing and dicing from files.

In my work, I have a LOT of units of work processing in parallel on a grid.  I have GUIDs tagging each unit of work, and that GUID is the perfect key for a Map/Dictionary data structure.  There are times, though, that I want to get the values of the Map and sort by some value in the data itself.  The is important if I want to sort my results by elapsed time or some other interesting metric.

Here’s how you sort a Python Dictionary by some arbitrary value within the data structure:

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import time
 
work = {}
 
#
# create some sample data...
#
for i in range(10):
    key = "unit_%s" % i
    unitOfWork = {
        "id" : key,
        "data" : {
            "name" : "Turansky",
            "dob" : "03/28",
            "favoriteNumber" : int(time.time()) + i
        }
    }
    work[key] = unitOfWork
 
print "The 'work' dictionary will print the objects randomly..."
for i in work:
    print work[i]
 
print ""
print "Sprinkle some sorting magic..."
 
# but you want to sort the objects by favoriteNumber'
# get your values as a list... you want to use the list.sort() method
units = work.values()
 
# provide a lambda function that references your data structure
units.sort(key = lambda obj:obj["data"]["favoriteNumber"])
 
print ""
print "... and just like that, you have order."
for u in units:
    print u

Here is the output:

The 'work' dictionary will print the objects randomly...
{'data': {'dob': '03/28', 'favoriteNumber': 1242069926, 'name': 'Turansky'}, 'id': 'unit_5'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069925, 'name': 'Turansky'}, 'id': 'unit_4'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069928, 'name': 'Turansky'}, 'id': 'unit_7'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069927, 'name': 'Turansky'}, 'id': 'unit_6'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069922, 'name': 'Turansky'}, 'id': 'unit_1'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069921, 'name': 'Turansky'}, 'id': 'unit_0'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069924, 'name': 'Turansky'}, 'id': 'unit_3'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069923, 'name': 'Turansky'}, 'id': 'unit_2'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069930, 'name': 'Turansky'}, 'id': 'unit_9'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069929, 'name': 'Turansky'}, 'id': 'unit_8'}

Sprinkle some sorting magic...

... and just like that, you have order.
{'data': {'dob': '03/28', 'favoriteNumber': 1242069921, 'name': 'Turansky'}, 'id': 'unit_0'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069922, 'name': 'Turansky'}, 'id': 'unit_1'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069923, 'name': 'Turansky'}, 'id': 'unit_2'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069924, 'name': 'Turansky'}, 'id': 'unit_3'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069925, 'name': 'Turansky'}, 'id': 'unit_4'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069926, 'name': 'Turansky'}, 'id': 'unit_5'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069927, 'name': 'Turansky'}, 'id': 'unit_6'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069928, 'name': 'Turansky'}, 'id': 'unit_7'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069929, 'name': 'Turansky'}, 'id': 'unit_8'}
{'data': {'dob': '03/28', 'favoriteNumber': 1242069930, 'name': 'Turansky'}, 'id': 'unit_9'}