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How to calculate relative frequency in Python?

By Shivang Yadav Last updated : November 21, 2023

Relative Frequency

Relative frequency is the count of occurrences of a value in a dataset relative to the total number of values present in the dataset.

Python provides multiple methods to calculate the relative frequency.

Calculation of Relative Frequency

As we know it is the portion of total frequency taken by the value, it can be easily calculated as:

Relative Frequency = (count of  value's occurrence)/(Total occurrence )

For this, we will be simply using a counter for counting occurrence and length method to find the total occurrence.

Example 1: Python program to calculate relative frequency of a list of numbers

# Program to Calculate Relative Frequency 
# in Python of a list

def calcRelFreq(x):
    relFreq = [(value, x.count(value) / len(x)) for value in set(x)]
    return relFreq

dataValues = [1, 1, 1, 2, 3, 4, 4, 5, 2, 5]
print("The values of dataset are ", dataValues)

relFreq = calcRelFreq(dataValues)
print("The relative frequency of dataset is ", relFreq)

Output

The output of the above program is:

The values of dataset are  [1, 1, 1, 2, 3, 4, 4, 5, 2, 5]
The relative frequency of dataset is  [(1, 0.3), (2, 0.2), (3, 0.1), (4, 0.2), (5, 0.2)]

Calculation of Relative Frequency of a Column in DataFrame

In a similar way, we can calculate the relative frequency for values of a column in a dataFrame, we just need to pass the column in the function.

Example 2: Python program to calculate the relative frequency of a DataFrame column

# Program to calculate relative frequency in Python
# of a DataFrame Column
import pandas as pd

def calcRelFreq(x):
    relFreq = [(value, x.count(value) / len(x)) for value in set(x)]
    return relFreq

dataValues = pd.DataFrame(
    {
        "english": ["A", "B", "A", "A", "C", "B", "D"],
        "hindi": ["B", "B", "C", "A", "A", "D", "D"],
    }
)
print("The values of dataset are ", dataValues)

relFreq = calcRelFreq(list(dataValues["hindi"]))
print("The relative frequency of dataset is ", relFreq)

Output

The output of the above program is:

The values of dataset are    english hindi
0       A     B
1       B     B
2       A     C
3       A     A
4       C     A
5       B     D
6       D     D
The relative frequency of dataset is  [('D', 0.2857142857142857), ('C', 0.14285714285714285), ('A', 0.2857142857142857), ('B', 0.2857142857142857)]

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