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A structure array is a particular instance of a structure, where each of the fields of the structure is represented by a cell array. Each of these cell arrays has the same dimensions. Conceptually, a structure array can also be seen as an array of structures with identical fields. An example of the creation of a structure array is
x(1).a = "string1"; x(2).a = "string2"; x(1).b = 1; x(2).b = 2;
which creates a 1-by-2 structure array with two fields. Another way
to create a structure array is with the struct
function
(see Creating Structures). As previously, to print the value of
the structure array, you can type its name:
x ⇒ x = { 1x2 struct array containing the fields: a b }
Individual elements of the structure array can be returned by indexing
the variable like x(1)
, which returns a structure with
two fields:
x(1) ⇒ ans = { a = string1 b = 1 }
Furthermore, the structure array can return a comma separated list of field values (see Comma Separated Lists), if indexed by one of its own field names. For example:
x.a ⇒ ans = string1 ans = string2
Here is another example, using this comma separated list on the left-hand side of an assignment:
[x.a] = deal ("new string1", "new string2"); x(1).a ⇒ ans = new string1 x(2).a ⇒ ans = new string2
Just as for numerical arrays, it is possible to use vectors as indices (see Index Expressions):
x(3:4) = x(1:2); [x([1,3]).a] = deal ("other string1", "other string2"); x.a ⇒ ans = other string1 ans = new string2 ans = other string2 ans = new string2
The function size
will return the size of the structure. For
the example above
size (x) ⇒ ans = 1 4
Elements can be deleted from a structure array in a similar manner to a numerical array, by assigning the elements to an empty matrix. For example
in = struct ("call1", {x, Inf, "last"}, "call2", {x, Inf, "first"}) ⇒ in = { 1x3 struct array containing the fields: call1 call2 } in(1) = []; in.call1 ⇒ ans = Inf ans = last
Next: Creating Structures, Previous: Basic Usage and Examples, Up: Structures [Contents][Index]