Understanding Lists in X++ Language

 

Introduction:

X++ is a versatile programming language used in Microsoft Dynamics 365 Finance and Operations (D365 F&O) for developing robust business applications. One of the powerful data structures in X++ is the list. In this blog post, we will explore the concept of lists, their features, and how they can be leveraged for efficient data manipulation.

1. What is a List?

A list in X++ is a dynamic data structure that allows you to store and manage a collection of elements of the same type. Unlike fixed-size arrays, lists have a dynamic size that can grow or shrink based on the number of elements. This flexibility makes lists an excellent choice for handling varying amounts of data.

2. Declaring and Initializing a List:

To create a list, you need to declare it with the desired element type and initialize it. Here's an example:

List myList = new List();

3. Adding Elements:

You can add elements to a list using the `addEnd()` method, which appends an element at the end of the list. Alternatively, the `add()` method allows you to insert an element at a specific index.

myList.addEnd(5); // Appends 5 at the end of the list
 

4. Accessing Elements:

Elements in a list can be accessed using their index. X++ lists use 1-based indexing, where the first element is at index 1.

int element = myList[3]; // Retrieves the element at index 3

5. Removing Elements:

6. Iterating through a List:

Conclusion:

Lists are valuable data structures in X++ that provide flexibility and efficiency in handling collections of elements. With their dynamic size and various methods for manipulation, lists empower developers to effectively manage data in X++ applications. By leveraging lists, you can build more scalable and maintainable solutions in Microsoft Dynamics 365 Finance and Operations.

Note: The examples and code snippets provided in this blog post are intended for illustrative purposes and may need to be adapted based on specific requirements and coding practices.

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code

internal final class ListClass
{
    /// <summary>
    /// Class entry point. The system will call this method when a designated menu 
    /// is selected or when execution starts and this class is set as the startup class.
    /// </summary>
    /// <param name = "_args">The specified arguments.</param>
    public static void main(Args _args){
        List myList = new List(Types::Integer);
        List myListString = new List(Types::String);
        ListIterator literator;

            myList.addStart(12);

        // add the element at the end of the list
        //
        myList.addEnd(2);

        // add the element at the start of the list
        myList.addStart(3);

        myList.addEnd(7);

        myListString.addEnd("Second");
        myListString.addStart("First");
        myListString.addEnd("Third");
        myListString.addEnd("Fourth");

        // If you want to insert the data at some specific index, then you need to make use of the listIterator class
        // Iterator performs a midpoint

        // insert at current position.
        literator = new ListIterator(myListString);

        while (literator.more())
        {
            // can provide some condition, i.e. if check etc
            if (literator.value())
            {
                Info(strFmt("%1 ", literator.value() ));
                literator.next();
              
            }
            else
            {
                break;
            }
        }

    }

}