List frequency of elements in Python

PythonServer Side ProgrammingProgramming

In this article, we are going to learn how to find the frequency of elements in a list. We can solve the problem in different ways. Let's see two of them.

Follow the below steps to write the code.

  • Initialize the list with elements and an empty dictionary.
  • Iterate over the list of elements.
    • Check whether the element is present in the dictionary or not.
    • If the element is already present in the dictionary, then increase its count.
    • If the element is not present in the dictionary, then initialize its count with 1.
  • Print the dictionary.

Example

Let's see the code.

 Live Demo

# initializing the list
random_list = ['A', 'A', 'B', 'C', 'B', 'D', 'D', 'A', 'B']
frequency = {}

# iterating over the list
for item in random_list:
   # checking the element in dictionary
   if item in frequency:
      # incrementing the counr
      frequency[item] += 1
   else:
      # initializing the count
      frequency[item] = 1

# printing the frequency
print(frequency)

If you run the above code, then you will get the following result.

Output

{'A': 3, 'B': 3, 'C': 1, 'D': 2}

Follow the below steps to the problem in another way. We are going to use a module method to find the frequency of elements.

  • Import the collections module.
  • Initialize the list with elements.
  • Get the frequency of elements using Counter from collections module.
  • Convert the result to dictionary using dict and print the frequency.

Example

Let's see the code.

# importing the module
import collections

# initializing the list
random_list = ['A', 'A', 'B', 'C', 'B', 'D', 'D', 'A', 'B']

# using Counter to find frequency of elements
frequency = collections.Counter(random_list)

# printing the frequency
print(dict(frequency))
{'A': 3, 'B': 3, 'C': 1, 'D': 2}

If you run the above code, then you will get the following result.

Output

{'A': 3, 'B': 3, 'C': 1, 'D': 2}

Conclusion

If you have any queries in the article, mention them in the comment section.

raja
Published on 13-Nov-2020 22:27:18
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