Compare Each Element of Two Lists in Python (2 Examples)

In this tutorial, you will learn how to compare each possible pair of two lists in Python Programming Language. Comparing each possible pair of two lists involves checking the relationship between every pair of elements from the two lists. We will explore different methods to achieve this comparison.

The table of contents is structured as follows:

Let’s get started!

Initializing Sample Lists

First, let’s initialize two sample lists:

# Initializing sample lists
list1 = [1, 3, 5]
list2 = [2, 4, 6]

These lists, list1 and list2, contain some elements for comparison.

Example 1: Comparison of Two Lists Using Nested for Loops

One way to compare each possible pair of two lists is using nested loops to iterate over every combination of elements. Here’s an example:

# Compare each possible pair using nested loops
pair_comparison = []
for item1 in list1:
    for item2 in list2:
        if item1 > item2:
            pair_comparison.append("greater")
        elif item1 < item2:
            pair_comparison.append("smaller")
        else:
            pair_comparison.append("equal")
 
# Print the comparison results
print(pair_comparison)  
# ['smaller', 'smaller', 'smaller', 'greater', 'smaller', 'smaller', 'greater', 'greater', 'smaller']

In this example, we use nested for loops to iterate over every possible combination of elements from list1 and list2. We compare each pair of elements and append the comparison results to the pair_comparison list. Finally, we print the comparison results.

Example 2: Comparison of Two Lists Using List Comprehension

Another way to compare each possible pair of two lists is using list comprehension and the itertools.product() function. Here’s how you can do it:

import itertools
 
# Compare each possible pair using list comprehension
pair_comparison = ["greater" if item1 > item2 else "smaller" if item1 < item2 else "equal" for item1, item2 in itertools.product(list1, list2)]
 
# Print the comparison results
print(pair_comparison) 
# ['smaller', 'smaller', 'smaller', 'greater', 'smaller', 'smaller', 'greater', 'greater', 'smaller']

In this example, we use the itertools.product() function to generate all possible pairs of elements from list1 and list2 and list comprehension to compare each pair of elements and store the comparison results directly in the pair_comparison list. Finally, we print the comparison results.

Video, Further Resources & Summary

In this tutorial, we explored different methods to compare each possible pair of two lists in Python. We learned how to use nested loops and list comprehension along with the `itertools.product` function to compare every pair of elements. These techniques can be helpful in scenarios where you need to analyze the relationship between all possible pairs of elements from two lists.

Do you need more explanations on looping through a list of integers in Python? Then you should have a look at the following YouTube video of the Statistics Globe YouTube channel.

The YouTube video will be added soon.

For more Python programming tutorials and examples, you can check out the following resources on Statistics Globe:

• Iterate Over Nested Dictionary with List in Python (Example)
• Combine Two Lists into 2D Array in Python (2 Examples)
• How to Use Lists in Python (13 Examples)
• Python Programming Language for Statistics & Data Science
• Find Common Elements in Three Lists in Python (3 Examples)

Now you have the knowledge and techniques to compare each possible pair of two lists in Python. Happy coding!

This page was created in collaboration with Ömer Ekiz. Have a look at Ömer’s author page to get more information about his professional background, a list of all his tutorials, as well as an overview of his other tasks on Statistics Globe.