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Determine number of values to return from customized indexing operations beginning with braces

Since R2021b


n = braceListLength(obj,indexOp,indexContext)


n = braceListLength(obj,indexOp,indexContext) determines the number of values to return from customized indexing operations that begin with braces and that reference or assign to comma-separated lists. Operations that begin with brace indexing and end with dot or brace indexing produce comma-separated lists, such as [C{:}] = obj{1:3} and [obj{1}.prop{1:3}] = B{:}. The indices being changed and the types of indexing operations are described in indexOp, and indexContext identifies whether the reference is used in a statement, as a list of arguments to a function, or in an assignment operation.

Input Arguments

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Object that implements customized brace indexing by inheriting from matlab.mixin.indexing.RedefinesBrace.

Types of indexing operations and indices referenced, specified as an array of IndexingOperation objects. For a brace reference, the first object in the array has a Type property of Brace.

Context in which the indexing operation occurs, specified as one of these enumeration members:

  • matlab.indexing.IndexingContext.Statement — Indexed reference used as a statement (for example, obj.a)

  • matlab.indexing.IndexingContext.Expression — Indexed reference used as an argument to a function (for example, func(obj.a))

  • matlab.indexing.IndexingContext.Assignment — Indexed assignment (for example, [obj.a] = deal(x)).

Output Arguments

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Number of values to return from an indexing operation, specified as a nonnegative integer.



To learn about attributes of methods, see Method Attributes.


For an example of a class that implements custom brace indexing, see matlab.mixin.indexing.RedefinesBrace.

Version History

Introduced in R2021b