Merge two arrays and remove duplicates in MuleSoft 168

 Merge two arrays and remove duplicates in MuleSoft

There are two main ways to achieve merging arrays and removing duplicates in MuleSoft 4 using DataWeave:

Method 1: Using ++ (concatenation) and distinctBy

This method is straightforward and efficient. Here's the DataWeave code:

%dw 2.0
output application/json

var arr1 = [1, 2, 3, 4];
var arr2 = [3, 4, 5, 6];

// Concatenate the arrays
var merged = arr1 ++ arr2;

// Remove duplicates based on the value itself
var distinct = merged distinctBy $;

---

// Output: [1, 2, 3, 4, 5, 6]

Explanation:

1. We define two sample arrays arr1 and arr2.

2. The ++ operator concatenates these arrays into a new variable merged.

3. The distinctBy $ function removes duplicates from merged. It uses the element itself ($) as the criteria for uniqueness.

Method 2: Using map and filter

This method involves iterating through the arrays and checking for duplicates. It's slightly less efficient but offers more flexibility for conditional filtering.

%dw 2.0
output application/json

var arr1 = [1, 2, 3, 4];
var arr2 = [3, 4, 5, 6];

// Combine arrays with filtering
var allElements = arr1 map $ ++ arr2 filter not (arr1 contains $);

---

// Output: [1, 2, 3, 4, 5, 6]

Explanation:

1. We define two sample arrays again.

2. The map $ expression iterates through arr1 and creates a new array with each element.

3. We concatenate (++) this result with arr2.

4. The filter function removes elements from the combined array that already exist in arr1 using the contains operator.

Choosing the Right Method:

• For a simple merge and de-duplication scenario, Method 1 with ++ and distinctBy is recommended for efficiency.

• If you need to filter based on additional criteria beyond just duplicates, Method 2 with map and filter provides more control.