OrderedDict and a Normal Dictionary (dict)Python provides both dict (normal dictionary) and OrderedDict from the collections module. The key difference lies in how they maintain insertion order and handle performance.
dict)# Normal Dictionary (Python 3.7+ retains order)
my_dict = {"a": 1, "b": 2, "c": 3}
print(my_dict) # Output: {'a': 1, 'b': 2, 'c': 3}
* Insertion order is preserved.
* Faster than OrderedDict due to internal optimizations.
OrderedDict (Before Python 3.7, Required for Ordered Keys)move_to_end().from collections import OrderedDict
# Creating an OrderedDict
ordered_dict = OrderedDict()
ordered_dict["a"] = 1
ordered_dict["b"] = 2
ordered_dict["c"] = 3
print(ordered_dict) # Output: OrderedDict([('a', 1), ('b', 2), ('c', 3)])
* Ensures order even in Python versions below 3.7.
* Slightly slower due to extra overhead.
OrderedDictmove_to_end(key, last=True)Moves a key to the end (or start if last=False).
ordered_dict.move_to_end("b")
print(ordered_dict) # Output: OrderedDict([('a', 1), ('c', 3), ('b', 2)])
==)d1 = OrderedDict([("a", 1), ("b", 2)])
d2 = OrderedDict([("b", 2), ("a", 1)])
print(d1 == d2) # Output: False (Order matters)
* Unlike a normal dictionary, order matters in comparison.
| Feature | dict (Python 3.7+) |
OrderedDict |
|---|---|---|
| Maintains Order? | Yes | Yes |
| Performance | Faster | Slightly Slower |
| Extra Features | No | Yes (move_to_end(), order-sensitive equality) |
| Use Case | General-purpose | When explicit ordering control is needed |
* Use dict in Python 3.7+ unless you need OrderedDict's extra features.