Welcome to this lesson on Intermediate Array Operations. Building on the basics of array manipulation, we’ll explore more intermediate techniques and develop a deeper understanding of how arrays function. Ruby offers many built-in methods for handling arrays, but learning to execute these operations manually strengthens your problem-solving skills and prepares you to create custom solutions when needed.

Let’s look at an operation that calculates the sums of all unique pairs within an array. Given an array, we’ll find and collect the sum of every unique pair of elements, skipping duplicates. This type of operation gives insight into pairwise comparisons, a foundational concept in more intermediate algorithms.

Here’s how it might look:

Ruby
Copy to clipboard
1# Find the sum of all unique pairs in an array without built-in methods
2def pair_sums(arr)
3  sums = []
4  i = 0
5  while i < arr.length
6    j = i + 1
7    while j < arr.length
8      sums << arr[i] + arr[j]
9      j += 1
10    end
11    i += 1
12  end
13  sums
14end
15
16# Example usage
17sample_array = [1, 2, 3, 4]
18puts pair_sums(sample_array).inspect  # Output: [3, 4, 5, 5, 6, 7]

This example demonstrates how to loop through an array to find the sums of unique pairs without using built-in methods, a common technique in intermediate array operations.

With these concepts in mind, let’s put them to the test in some hands-on exercises. Remember, we’re not just learning specific techniques but enhancing our ability to break down and solve problems with clear, efficient code. Let’s dive into the practice!