如何习惯性地对 Python 中的嵌套字典键进行排序

Question

I have a dictionary like:

my_dict = {
    'KEY1': [
        {'date': 20100701, 'name': 'google', 'stock': 10},
        {'date': 20100705, 'name': 'facebook', 'stock': 10}],
    'KEY2': [
        {'date': 20071010, 'name': 'amex', 'stock': 110},
        {'date': 20071020, 'name': 'c1', 'stock': 110}],
    'KEY3': [
        {'date': 20100710, 'name': 'microsoft', 'stock': 100},
        {'date': 20100710, 'name': 'uber', 'stock': 100}]
}

I want the nested dictionary's key in such order: [name, date, stock]

I have checked other links with sorted and orderdict examples but can't still figure out how to use them in my case. How can this be done?

Answer 1

You can use nested dict/list comprehensions like this:

{k: [{i: d[i] for i in ('name', 'date', 'stock')} for d in l] for k, l in my_dict.items()}

This returns:

{'KEY1': [{'name': 'google', 'date': 20100701, 'stock': 10}, {'name': 'facebook', 'date': 20100705, 'stock': 10}], 'KEY2': [{'name': 'amex', 'date': 20071010, 'stock': 110}, {'name': 'c1', 'date': 20071020, 'stock': 110}], 'KEY3': [{'name': 'microsoft', 'date': 20100710, 'stock': 100}, {'name': 'uber', 'date': 20100710, 'stock': 100}]}

Or if you are using Python 3.6 or earlier versions, you can use collections.OrderedDict instead:

OrderedDict((k, [OrderedDict((i, d[i]) for i in ('name', 'date', 'stock')) for d in l]) for k, l in my_dict.items())

This returns:

OrderedDict([('KEY1', [OrderedDict([('name', 'google'), ('date', 20100701), ('stock', 10)]), OrderedDict([('name', 'facebook'), ('date', 20100705), ('stock', 10)])]), ('KEY2', [OrderedDict([('name', 'amex'), ('date', 20071010), ('stock', 110)]), OrderedDict([('name', 'c1'), ('date', 20071020), ('stock', 110)])]), ('KEY3', [OrderedDict([('name', 'microsoft'), ('date', 20100710), ('stock', 100)]), OrderedDict([('name', 'uber'), ('date', 20100710), ('stock', 100)])])])