Code Explanation of List Operations in Python

Code Snippet

list1 = [7, 10, 14, 18]
list2 = [3, 8, 9, 15]
result = [a - b for a, b in zip(list1, list2)]

print(result)

Overview

This code snippet demonstrates the creation of two lists and the computation of their element-wise differences using a list comprehension in Python. The final result is printed out.

Breakdown of Key Components

1. List Creation

list1 = [7, 10, 14, 18]
list2 = [3, 8, 9, 15]

• Explanation: Two lists named list1 and list2 are defined. list1 contains integers [7, 10, 14, 18], and list2 contains integers [3, 8, 9, 15].
• Purpose: These lists serve as input data for later calculations.

2. Element-wise Operations using zip()

result = [a - b for a, b in zip(list1, list2)]

• zip(list1, list2):

  • Functionality: The zip() function combines the elements of list1 and list2 into pairs (tuples). For the given lists, it creates the following pairs: (7, 3), (10, 8), (14, 9), (18, 15).

• List Comprehension:

  • This syntax [a - b for a, b in ...] is called a list comprehension, which provides a concise way to create a new list.
  • Operation: For every pair of elements (a, b) created by zip(), it computes a - b (subtracts the corresponding elements of list2 from list1).

• Result of the Operation:

  • The computations performed by the list comprehension yield the following differences: 7 - 3 = 4, 10 - 8 = 2, 14 - 9 = 5, and 18 - 15 = 3. Thus, result will be [4, 2, 5, 3].

3. Output the Result

print(result)

• Functionality: This line prints the computed list result to the console.
• Expected Output: The output will be:

  [4, 2, 5, 3]

Summary of the Code Functionality

• The code initializes two lists of integers.
• It computes an element-wise difference between these lists using zip() with list comprehension.
• Finally, it displays the resulting list of differences.

Key Concepts Explained

• List Comprehension: A syntactical construct to create lists based on existing lists in a readable and concise manner.
• zip() Function: Combines multiple iterables (like lists) into tuples, making it easier to iterate through corresponding items from each iterable.

Additional Example

Here is an alternative example illustrating the same concept of element-wise operations:

list_a = [5, 12, 20]
list_b = [1, 4, 10]
difference = [x - y for x, y in zip(list_a, list_b)]

print(difference)

• Expected Output:

  [4, 8, 10]

• This example highlights how to apply the same pattern with different sets of lists.

Conclusion

This code example illustrates fundamental Python operations involving lists, showcasing how to effectively compute differences between corresponding elements in two lists. To deepen understanding, further exploration of list comprehensions and the zip() function, as well as practice with different mathematical operations, is recommended. For additional learning resources, consider exploring courses offered through the Enterprise DNA Platform.