The Python dictionary can be sorted by value through the sorted() function and returns the results in the form of a list. 1. Use operator.itemgetter to read highly, and after the operator import itemgetter, it is implemented through sorted(data.items(), key=itemgetter(1)); 2. You can use lambda expressions to not import the module, sorted(data.items(), key=lambda x: x[1]) has the same effect; 3. If dictionary output is required, use dict(sorted_data) to convert the list. Note that the order is only retained in Python 3.7. The old version considers collections.OrderedDict.
Sure, sorting a Python dictionary by value is something you'll probably need to do pretty often. The good news is, it's straightforward once you know the right method.
Use sorted() with operator.itemgetter for clean code
The most common and readable way is to use the sorted() function along with either a lambda or operator.itemgetter . Here's how it works:
- Dictionaries themselves can't be sorted directly, so this method returns a list of tuples.
- You specify that you want to sort by value (which is the second item in each key-value pair).
Example:
from operator import itemgetter
data = {'apple': 3, 'banana': 1, 'cherry': 2}
sorted_data = sorted(data.items(), key=itemgetter(1)) This will give you a list like [('banana', 1), ('cherry', 2), ('apple', 3)] .
If you're working with just the values ??and don't care about keys, you could also extract values ??first using .values() , but that loses the connection between keys and values.
Use a lambda if you prefer not to import anything
If you'd rather avoid importing from the operator module, you can achieve the same result with a lambda function inside sorted() .
This approach might feel more lightweight, especially for small scripts or quick tasks where importing modules feels unnecessary.
Example:
data = {'apple': 3, 'banana': 1, 'cherry': 2}
sorted_data = sorted(data.items(), key=lambda x: x[1]) You get the same result — a list of key-value pairs sorted by value.
It's up to personal preference whether to use itemgetter or a lambda. Both are widely accepted.
What if you want a dictionary back?
After sorting, you'll notice that the result is a list of tuples, not a dictionary. If you want to turn it back into a dictionary (especially in Python 3.7 , where dictionaries preserve insertion order), here's what you do:
sorted_dict = dict(sorted_data)
Just keep in mind:
- This only works after you've already sorted the items.
- The resulting "sorted dictionary" will maintain that order when printed or iterated — but only in Python 3.7 and above.
If you're stuck on an older version or working in a context where order isn't preserved, consider using collections.OrderedDict instead.
That's basically all there is to it. It's not complicated, but it's easy to forget exactly how the syntax works if you don't do it every day.
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