List the frequency of elements in Python
In a language used for programming, data structures are very important. The secret to developing reliable and effective programs is knowing how to handle, store, and alter data.
A list is one of the pre-built structures for data in Python; it is a set of data points enclosed in a pair of square brackets. Lists can hold any kind of data or a combination of various types.
A list is a series of ordered, indexed values like an array. Because it is malleable, we can alter a list's elemental order. Python lists are linear data structures that can store various elements. It can expand and contract without having to be declared.
Dynamically scaled arrays and Python lists share similarities. They are employed to store a variety of data forms. Lists in Python are mutable, meaning that changes can be made to their elements after they are formed. Another definition of a Python list is an assortment of values or objects. The list's elements are encircled by the square brackets [] and separated by commas (,).
The data types like Strings, Objects, and Integers can all be found in a single list. Because lists are adaptable, they can be modified even after making them. The fact that each element in the list has a distinct location permits a duplicate of elements within the list, with everyone having a unique placement.
Count frequency in the list using a for loop.
The frequency of each member in a list can be determined by employing a dictionary and a for loop. We make an empty dictionary with the keys being the unique entries from the supplied list and the values being their counts. We iterate over the list of elements after initializing the list with items and vacant dictionaries. We determine that the element is in the list of elements inside the loop. Increase the element's count if it has been included in the thesaurus. Additionally, set the component's value to 1 if it is absent from the dictionary.
To write the code, follow the instructions below.
- Add elements to the list and start it with a blank dictionary.
- Repeat through the elements on the list.
- Verify whether or not the element is listed in the dictionary.
- Increment an element's count if it already exists in the dictionary.
- Initialize the component's count to 1 if it is absent from the dictionary.
- Get the dictionary printed.
Code:
list = ['23', '23', '42', '27', '42', '27', '27', '71', '62']
dict = {}
# iterating over the list
for items in the list:
# checking the element in the dictionary
If items in dict:
# Incrementing the county
dict[items] += 1
Else:
# initializing the county
dict[items] = 1
# printing the frequency
print(dict)
Output:
Python's Collections module includes structures for storing data collections, such as lists, dicts, sets, tuples, etc. Initially, use the subsequent command to install the collection module:
Installing Collections in Python
We import the set module and initialize the list with elements in the example provided. The Collection module contains the Python Counter class. It belongs to the dictionary's class. Language values are used to record counts of items and keys for dictionary entries are used to store contents. This allows us to obtain the occurrence of every entry in a list. Lastly, we use the dict to turn the result into a list of words and output the number of times.
The steps to solve the problem using a different approach are as follows. We shall employ the module method to ascertain the occurrence of the elements.
- Bring in the collection module.
- Add elements to the list to start.
- Use the Counter function from the collection module to find the frequency of each component.
- Use dict() to transform the output to dictionaries, then print the frequency.
Code:
import collections
# initializing list
list = ['19', '19', '42', '27', '42', '27', '27', '19', '27']
# using Counter to find the frequency of elements
freq = collections.Counter(list)
# printing the frequency
print(dict(freq))
Output: