How do you retrieve items from a dictionary in the order that they're inserted?

The standard Python dict does this by default if you're using CPython 3.6+ (or Python 3.7+ for any other implementation of Python).

On older versions of Python you can use collections.OrderedDict.

The other answers are correct; it's not possible, but you could write this yourself. However, in case you're unsure how to actually implement something like this, here's a complete and working implementation that subclasses dict which I've just written and tested. (Note that the order of values passed to the constructor is undefined but will come before values passed later, and you could always just not allow ordered dicts to be initialized with values.)

class ordered_dict(dict):
    def __init__(self, *args, **kwargs):
        dict.__init__(self, *args, **kwargs)
        self._order = self.keys()

    def __setitem__(self, key, value):
        dict.__setitem__(self, key, value)
        if key in self._order:
            self._order.remove(key)
        self._order.append(key)

    def __delitem__(self, key):
        dict.__delitem__(self, key)
        self._order.remove(key)

    def order(self):
        return self._order[:]

    def ordered_items(self):
        return [(key,self[key]) for key in self._order]


od = ordered_dict()
od["hello"] = "world"
od["goodbye"] = "cruel world"
print od.order()            # prints ['hello', 'goodbye']

del od["hello"]
od["monty"] = "python"
print od.order()            # prints ['goodbye', 'monty']

od["hello"] = "kitty"
print od.order()            # prints ['goodbye', 'monty', 'hello']

print od.ordered_items()
# prints [('goodbye','cruel world'), ('monty','python'), ('hello','kitty')]

Use OrderedDict(), available since version 2.7

Just a matter of curiosity:

from collections import OrderedDict
a = {}
b = OrderedDict()
c = OrderedDict()

a['key1'] = 'value1'
a['key2'] = 'value2'

b['key1'] = 'value1'
b['key2'] = 'value2'

c['key2'] = 'value2'
c['key1'] = 'value1'

print a == b  # True
print a == c  # True
print b == c  # False