Containers

Containers

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Microsoft Dynamics AX 4

Containers

X++ has a general data type called a container that can be regarded as a dynamic untyped array of primitive data types, containers, and arrays.

The elements of a container can be any combination of valid types, in any order, including nested containers. A number of functions are provided to manipulate the values inside a container.

Range of containers

Containers are dynamic and have no limits. They can contain elements of almost all data types: boolean, integer, real, date, string, container, arrays, tables, and extended data types. However, objects cannot be stored in containers.

Note
Variables in objects and fields in tables can be declared as containers.

Declaring and initializing containers

container declaration	=	container Variable { , Variable } ;
Variable	=	Identifier [ option ]
Option	=	Arrayoptions \| initialization

// Declaration of a container, c1
container c1;
// A dynamic array of containers is declared
container c2[];
// A container is declared and initialized with three items:
// an integer (1), a real (3.14), and a string "a".
container c3 = [1,3.14,"a"];

Note
You cannot add more than 40 elements to a container at one time. You can add additional elements as shown in the following example. c3 += [23,34,55,62,73];//additional elements You may use the += operator to add values of any type into a container. For example, to create a container containing the first ten square numbers: int i; container c; ; for (i = 1; i <= 10; i++) { c += i+i; }

Note

You cannot add more than 40 elements to a container at one time. You can add additional elements as shown in the following example.

c3 += [23,34,55,62,73];//additional elements

You may use the += operator to add values of any type into a container. For example, to create a container containing the first ten square numbers:

int i;

container c;

;

for (i = 1; i <= 10; i++)

{

c += i+i;

}

Container Literals

Although containers are a list of values, you can specify literals for them. Use the square brackets around the elements in the container:

container c = [1,3.14,"abc"];

Automatic Conversion

When you use built-in functions to manipulate containers, the elements are automatically converted into the result type. The following example inserts a string and a real, respectively, into a container, and then fetches the items again but in reverse order. The string is fetched into a real and the real is fetched into a string.

real r = 0;
str 30 s = "";
container c = ["3.14",3.14];
;
s = conpeek(c,2);
r = conpeek(c,1);

The result is that s = "3.14" and r = 3.14. The conpeek function has converted the item to the correct type. For more information, see conPeek Function.

Overview of Containers

Keyword	container
Size of data type	Dynamic
Scope of data type	User-defined
Default value	0
Implicit conversions	None
Explicit conversions	None