Skip to main content

How to find the mode of elements in a list in Python

How to find the mode of elements in a list in Python.

Here's a step-by-step tutorial on finding the mode of elements in a list in Python:

Step 1: Create a list of elements​

Start by creating a list of elements for which you want to find the mode. For example, let's say we have the following list:

numbers = [1, 2, 3, 4, 4, 4, 5, 5, 6, 6, 6, 7, 8, 9]

Step 2: Create a dictionary to count the frequency of each element​

To find the mode, we need to count the frequency of each element in the list. We can use a dictionary to store the element as the key and its frequency as the value. We'll initialize an empty dictionary to start:

frequency = {}

Step 3: Iterate through the list and count the frequency of each element​

Next, we'll iterate through the list and count the frequency of each element. We'll use a for loop to iterate over each element in the list. If the element is already in the dictionary, we'll increment its frequency by 1. Otherwise, we'll add the element to the dictionary with a frequency of 1.

for num in numbers:
    if num in frequency:
        frequency[num] += 1
    else:
        frequency[num] = 1

Step 4: Find the mode(s) with the highest frequency​

After counting the frequency of each element in the list, we need to find the mode(s) with the highest frequency. We can use the max() function to get the maximum frequency from the dictionary. Then, we'll iterate through the dictionary and check which element(s) have the maximum frequency.

max_frequency = max(frequency.values())

mode = [num for num, freq in frequency.items() if freq == max_frequency]

Step 5: Print the mode(s) of the list​

Finally, we'll print the mode(s) of the list. If there is more than one mode, we'll print all of them.

print("Mode(s) of the list:", mode)

Putting it all together, here's the complete code:

numbers = [1, 2, 3, 4, 4, 4, 5, 5, 6, 6, 6, 7, 8, 9]

frequency = {}

for num in numbers:
    if num in frequency:
        frequency[num] += 1
    else:
        frequency[num] = 1

max_frequency = max(frequency.values())
mode = [num for num, freq in frequency.items() if freq == max_frequency]

print("Mode(s) of the list:", mode)

Output:

Mode(s) of the list: [4, 6]

In this example, the mode of the list [1, 2, 3, 4, 4, 4, 5, 5, 6, 6, 6, 7, 8, 9] is [4, 6] since these elements have the highest frequency of 3.