Sorting a Dictionary with Python
Any computer language’s essential building blocks are data structures. One needs to be skilled in making effective use of data structures in order to produce reliable and effective software.
Dictionaries are one of the most frequently used built-in data structures in Python, along with Lists, Tuples, and Sets. A Dictionary with Python is a collection of key-value pairs that are not ordered. The values are accessed using the keys, as the name implies. We are allowed to use strings, numbers (int or float), or tuples as keys as long as they are immutable and unique. Values, on the other hand, come in many different types.
A dictionary’s items (i.e., key-value pairs) are not by default sorted and do not have an index. However, Python allows us to sort dictionaries either by key or by value. In this tutorial, we’ll go through in great detail how to sort a dictionary in Python. Check out our online Python course if you’re new to Python and don’t know anything about data structures.
How to Create a Dictionary with Python
In Python, a dictionary can be created in a variety of ways. The use of zero or more key-value pairs enclosed in curly brackets is one approach.
The names are the keys, and the letter grades are the values, in four key-value pairs that make up the grades dictionary.
The dict() constructor can also be used to create a dictionary. The list of tuples, each of which represents a key-value pair, can be used to pass the key-value pairs.
Instead of utilising a list of tuples when the keys are straightforward strings, we can define key-value pairs using keyword parameters in the dict() constructor.
The sorted() Function
The sorted() method, which accepts an iterable as an input and returns a sorted version of that iterable, must be understood.
One of Python’s built-in functions is called sorted(). Knowing and utilising built-in functions and algorithms is essential to writing effective code and producing applications that are optimised.
The sorted() function does not affect the original variable, which in the example above is the names list, so it must be noted that it does not work in place. Instead, a modified form of the original variable is returned. We must either assign the sorted list of names to the variable itself or a new one before we can utilise it.
The keys and reverse arguments are two additional optional arguments that the sorted() function accepts. When set to “True,” the reverse argument’s self-explanatory value causes the sorting operation to be performed in reverse order.
It makes sense to sort strings in alphabetical order when sorting a list of strings. Similar to this, depending on the value of the reverse argument, a numeric iterable is sorted in either rising or decreasing order.
With the key parameter, the sorted() function can also be utilized for trickier sorting tasks.
The initial elements (i.e., the keys) of a tuple, in this case, employee names, are sorted by default. What if we wanted to order the key-value pairs in these tuples according to the values of the second element? The key parameter can be applied in this situation. The second item from each tuple is taken by the lambda function that is used as the key parameter. The key and reverse arguments can also be used in tandem.
How to Sort a Dictionary in Python
Dictionary Keys, Values, and Items
Let’s first learn how to extract bits of information from a dictionary before we sort a dictionary in Python.
Key-value pairs make up a dictionary, as was previously established. Using the keys() and values() methods, we may separate the keys and values from a dictionary.
The items() method can also be used to extract key-value pairs as a list of tuples.
Dictionary Sorting by Key and Value
We must first take the items, or key-value pairs, in order to sort a dictionary by keys or values. Then, using the key parameter of the sorted() method, we can select either keys or values with indexing. The first element (with index 0) is the key, and the second element (with index 1) is the value since an item is extracted as a tuple of a key and a value. Not a dictionary, but a list of tuples should make up the final structure. This is a result of how the sorted() method, which provides a list of tuples, behaves. Simply apply the dict() constructor to the output of the sorted() function if you want the result to be a dictionary.
The output is still a dictionary. Keep in mind that the original dictionary hasn’t been changed, so workers. Instead, we made a fresh dictionary with things arranged according to keys. It can be kept in a fresh variable.
Conclusion You can check our Python training to learn more about Sorting in Python.
