Wednesday 21 February 2024

Can you explain what the window operator does in the context of dataweave? in MuleSoft 016

 Can you explain what the window operator does in the context of dataweave? in MuleSoft

In DataWeave for MuleSoft 4, the window operator provides powerful capabilities for working with sequences of data within a specific windowing context. It allows you to access and manipulate data elements not only based on their current position but also considering their relative positions within a defined window size.

Here's a breakdown of the key features and functionalities of the window operator:


Code snippet

[items: Array<T>] window (width: Integer) {
  // Logic to access and manipulate data within the window

  • items: The array you want to apply the windowing operation to.

  • T: Data type of elements in the array.

  • width: Size of the window (number of elements).

  • // Logic: Operations you want to perform on the data within the window.


  • The window operator iterates through the array, considering a window of width elements at a time.

  • Within each window, you can access the current element, previous elements, and subsequent elements based on their positions.

  • This allows you to perform calculations, comparisons, or transformations based on the relative positions of data points within the window.

Common Use Cases:

  • Aggregates within windows: Calculate running totals, averages, or other aggregations considering a specific window size.

  • Identifying trends and patterns: Analyze data within sliding windows to identify trends, changes, or outliers.

  • Implementing stateful logic: Utilize previous elements within the window to maintain state information for processing.

  • Performing window-based filtering: Select elements based on conditions involving their position and values within the window.


Code snippet

%dw 2.0

input = [10, 20, 30, 40, 50];

// Calculate moving average with window size 3
output = input window (width: 3) {

// Find elements greater than the previous element within the window
output = input window (width: 2) {
  if (item > values[0]) item else null


  • The window operator operates on arrays and processes elements in sequence.

  • Choose the appropriate width based on your desired analysis or calculation.

  • Refer to the DataWeave documentation for further details and advanced usage: [invalid URL removed]

By understanding and leveraging the window operator effectively, you can create versatile and powerful data processing logic in your DataWeave scripts for MuleSoft 4 applications, handling scenarios that require analysis or transformations based on windowing contexts.

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