Counting the Frequencies in a List Using Dictionary in Python
Last Updated : 10 Feb, 2025
Counting the frequencies of items in a list using a dictionary in Python can be done in several ways. For beginners, manually using a basic dictionary is a good starting point.
Using Manual Method
It uses a basic dictionary to store the counts, and the logic checks whether the item is already in the dictionary. If it is, the count is incremented; if it's not, the item is added to the dictionary with an initial count of 1.
Python a = ['apple', 'banana', 'apple', 'orange', 'banana', 'banana'] # Create an empty dictionary to store the counts b = {} # Loop through the list for c in a: # If the item is already in dictionary, increase its count if c in b: b[c] += 1 # If the item is not in dictionary, add it with a count of 1 else: b[c] = 1 print(b) Output{'apple': 2, 'banana': 3, 'orange': 1} Let's explore more methods to count the frequencies in a List Using Dictionory in Python.
Using a Default Dictionary (defaultdict)
The defaultdict from the collections module automatically initializes new keys with a default value (in this case, 0), so there's no need to explicitly check if the key exists before incrementing the count.
Python from collections import defaultdict # List of items a = ['apple', 'banana', 'apple', 'orange', 'banana', 'banana'] # Create a defaultdict with default value 0 b = defaultdict(int) # Loop through the list for c in a: b[c] += 1 # Print the frequency of each item print(dict(b))
Output{'apple': 2, 'banana': 3, 'orange': 1} Using get() Method
This will count the frequency of each item in the list using the get() method. The get() method is used to return the current count of an item or 0 if the item is not yet in the dictionary.
Python a = ['apple', 'banana', 'apple', 'orange', 'banana', 'banana'] # Create an empty dictionary to store the counts b = {} # Loop through the list for c in a: # Use get() to either return the current count or 0 #if the item is not in the dictionary b[c] = b.get(c, 0) + 1 print(b) Output{'apple': 2, 'banana': 3, 'orange': 1} Using List Comprehension
For small lists, we can also use a list comprehension along with the count() method to get the frequency of each item. But this method is not as efficient as the others since count() will loop through the entire list each time.
Python a = ['apple', 'banana', 'apple', 'orange', 'banana', 'banana'] # Create a list of unique items b = list(set(a)) # Use list comprehension to count the frequency of each unique item c = {item: a.count(item) for item in b} # Print the frequency of each item print(c) Output{'banana': 3, 'apple': 2, 'orange': 1} Similar Reads
Python - Convert Frequency dictionary to list When we convert a frequency dictionary to a list, we are transforming the dictionary into a list of key-value or just the keys/values, depending on needs. We can convert a frequency dictionary to a list using methods such as list comprehension, loops, extend() method and itertools.chain() function.F
3 min read
Python - Associated Values Frequencies in Dictionary Sometimes, while working with dictionaries, we can have problem in which we need to compute the values associated to each value in dictionary in records list. This kind of problem is peculiar, but can have application in development domains. Lets discuss certain way in which this task can be perform
5 min read
Count the Key from Nested Dictionary in Python In Python, counting the occurrences of keys within a nested dictionary often requires traversing through its complex structure. In this article, we will see how to count the key from the nested dictionary in Python. Count the Key from the Nested Dictionary in PythonBelow are some ways and examples b
4 min read
Count all Elements in a Nested Python Dictionary Nested dictionaries are a common data structure in Python, often used to represent complex relationships and hierarchies. When working with nested dictionaries, you may encounter situations where you need to count all the elements within them. In this article, we will explore some simple and commonl
3 min read
Python - Values frequency across Dictionaries lists Given two list of dictionaries, compute frequency corresponding to each value in dictionary 1 to second. Input : test_list1 = [{"Gfg" : 6}, {"best" : 10}], test_list2 = [{"a" : 6}, {"b" : 10}, {"d" : 6}}] Output : {'Gfg': 2, 'best': 1} Explanation : 6 has 2 occurrence in 2nd list, 10 has 1. Input :
6 min read