subsref (MATLAB Functions)

Overloaded method for A(I), A{I} and A.field

Syntax

```
B = subsref(A, S)
```

Description

B = subsref(A, S) is called for the syntax A(i), A{i}, or A.i when A is an object. S is a structure array with the fields

type: A string containing '()', '{}', or '.', where '()' specifies integer subscripts, '{}' specifies cell array subscripts, and '.' specifies subscripted structure fields.
subs: A cell array or string containing the actual subscripts.

Remarks

subsref is designed to be used by the MATLAB interpreter to handle indexed references to objects. Calling subsref directly as a function is not recommended. If you do use subsref in this way, it conforms to the formal MATLAB dispatching rules and can yield unexpected results.

If A is an array of one of the fundamental MATLAB data types, then referencing a value of A using an indexed reference calls the builtin MATLAB subsref method. It does not call any subsref method that you may have overloaded for that data type. For example, if A is an array of type double, and there is an @double/subsref method on your MATLAB path, the statement B = A(I) does not call this method, but calls the MATLAB builtin subsref method instead.

Examples

The syntax A(1:2,:) calls subsref(A,S) where S is a 1-by-1 structure with S.type='()' and S.subs={1:2,':'}. A colon used as a subscript is passed as the string ':'.

The syntax A{1:2} calls subsref(A,S) where S.type='{}' and S.subs={1:2}.

The syntax A.field calls subsref(A,S) where S.type='.' and S.subs='field'.

These simple calls are combined in a straightforward way for more complicated subscripting expressions. In such cases length(S) is the number of subscripting levels. For instance, A(1,2).name(3:5) calls subsref(A,S) where S is a 3-by-1 structure array with the following values:

S(1).type='()'
S(2).type='.'
S(3).type='()'

S(1).subs={1,2}
S(2).subs='name'
S(3).subs={3:5}

`S(1).type='()'`	`S(2).type='.'`	`S(3).type='()'`
`S(1).subs={1,2}`	`S(2).subs='name'`	`S(3).subs={3:5}`

See Also

subsasgn

See Handling Subscripted Reference for more information about overloaded methods and subsref.

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