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### 6.1.2 Structure Arrays

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 2-by-1 structure array with two fields. Another way to create a structure array is with the `struct` function (see section 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 section 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 section 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 ```

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