Table of Contents
- How to sort sort dictionary by value in Python?
- Using for loop along with the sorted() function.
- Using the sorted() function to sort dictionary by value in Python.
- Using operator.itemgetter() function to sort sort dictionary by value in Python.
- Using lambda function to sort sort dictionary by value in Python.
- Using the OrderedDict() method to sort sort dictionary by value in Python.
The elements of the given data might sometimes need sorting to make it easier to read, visualize and understand. This tutorial focuses on the different ways available to sort dictionary by value in Python.
What is a dictionary in Python?
Dictionaries are one of the four in-built data types that Python provides for the storage of data. It is utilized to store the elements in a variable in key:value
pairs. It does not allow duplicates and is ordered. Dictionaries were initially unordered until the release of Python 3.7.
Why is there a need to sort a dictionary?
The elements in a dictionary, as mentioned above, are stored in key:value
pairs. It is therefore very important to sort the data in a manner so that it is aesthetic and visually easy to understand.
How to sort sort dictionary by value in Python?
Using for
loop along with the sorted()
function.
This can be simply implemented by using a for
loop along with the sorted()
function. The sorted()
function is an in-built function that simply provides the sorted list of the given iterable, which in this case, is a dictionary.
The following code uses the for
loop along with the sorted()
function.
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dictx = {1: 5, 2: 10, 3: 8} sv = sorted(dictx.values()) sdictx = {} for i in sv: for k in dictx.keys(): if dictx[k] == i: sdictx[k] = dictx[k] break print(sdictx) |
The above code provides the following output:
Explanation:
- A dictionary
dictx
is declared and it’skey:value
pairs are defined. - The
sorted()
function is utilized on the given dictionary to order all the values of it. - Then, the
for
loop is utilized to find keys for each of the values present by iterating over the sorted values. - The
key:value
pairs that are found are then represented in the sorted order through a fresh dictionary.
We should note that by using the sorted()
function on the dictionary, we cannot change the order of a dictionary. We simply use a fresh dictionary to show the sorted elements.
Using the sorted()
function to sort dictionary by value in Python.
In the above method, we used the sorted()
function along with the for
loop. In this method, we will make use of a parameter that the sorted()
function takes in to sort dictionary by value in Python.
The sorted function is written as sorted(dictx, key=dictx.get)
. Here, the key
parameter is a method that comes into play every time the values need to be compared for sorting. The get()
method simply gets the values for the key of the dictionary.
The following code uses the sorted()
function to sort sort dictionary by value in Python.
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dictx = {1: 5, 2: 10, 3: 8} sdictx = {} skeys = sorted(dictx, key=dictx.get) for j in skeys: sdictx[j] = dictx[j] print(sdictx) |
The above code provides the following output:
The advantage that this method holds over the above-mentioned method is that the length of the code of the former is way less than that of the latter.
Using operator.itemgetter()
function to sort sort dictionary by value in Python.
The itemgetter()
function can be imported from the operator
module in Python. This function is utilized to simply provide the callable object that returns an item
from a given object.
The following code uses the operator.itemgetter()
function to sort sort dictionary by value in Python.
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import operator dictx = {1: 5, 2: 10, 3: 8} stuples = sorted(dictx.items(), key=operator.itemgetter(1)) sdictx = {i: x for i, x in stuples} print(sdictx) |
The above code provides the following output:
Explanation:
- A dictionary
dictx
is declared and it’skey:value
pairs are defined. - The dictionary is then sorted, and converted to a tuple with the help of the
sorted()
function and theoperator.itemgetter()
function. - The sorted tuple is then finally converted to a new dictionary and its values are displayed as the output.
Using lambda function to sort sort dictionary by value in Python.
Lambda functions can be simply defined as an unnamed or anonymous function, which has only a single expression but can have a countless number of arguments.
A lambda function can be utilized as an alternative to the operator.itemgetter()
function and does not need us to import the operator
module to the code.
The following code uses the lambda function to sort sort dictionary by value in Python.
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dictx = {1: 5, 2: 10, 3: 8} stuples = sorted(dictx.items(), key=lambda item: item[1]) sdictx = {i: x for i, x in stuples} print(sdictx) |
The above code provides the following output:
Explanation:
- A dictionary
dictx
is declared and it’skey:value
pairs are defined. - The dictionary is then sorted, and converted to a tuple with the help of the
sorted()
function and a lambda function. - The sorted tuple is then finally converted to a new dictionary and its values are displayed as the output.
Using the OrderedDict()
method to sort sort dictionary by value in Python.
The code can be further shortened by making use of the OrderedDict()
function. This function is a part of the collections
library, which needs to be imported to the python code for this method to work.
The following code uses the OrderedDict()
method to sort sort dictionary by value in Python.
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from collections import OrderedDict dictx = {1: 5, 2: 10, 3: 8} sdictx = OrderedDict(sorted(dictx.items(), key=lambda item: item[1])) print(sdictx) |
The above code provides the following output:
We should note that although it lessens the length of the code, this function displays the output as a dictionary-compatible type instead of an actual dictionary.
That’s all about how to sort dictionary in Python.