# Documentation

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## Create Structure Array

This example shows how to create a structure array. A structure is a data type that groups related data using data containers called fields. Each field can contain data of any type or size.

Store a patient record in a scalar structure with fields `name`, `billing`, and `test`.

```patient(1).name = 'John Doe'; patient(1).billing = 127.00; patient(1).test = [79, 75, 73; 180, 178, 177.5; 220, 210, 205]; patient```
```patient = struct with fields: name: 'John Doe' billing: 127 test: [3x3 double] ```

Add records for other patients to the array by including subscripts after the array name.

```patient(2).name = 'Ann Lane'; patient(2).billing = 28.50; patient(2).test = [68, 70, 68; 118, 118, 119; 172, 170, 169]; patient```
```patient = 1x2 struct array with fields: name billing test ```

Each patient record in the array is a structure of class `struct`. An array of structures is often referred to as a struct array. Like other MATLAB arrays, a struct array can have any dimensions.

A struct array has the following properties:

• All structs in the array have the same number of fields.

• All structs have the same field names.

• Fields of the same name in different structs can contain different types or sizes of data.

Any unspecified fields for new structs in the array contain empty arrays.

```patient(3).name = 'New Name'; patient(3)```
```ans = struct with fields: name: 'New Name' billing: [] test: [] ```

Access data in the structure array to find how much the first patient owes, and to create a bar graph of his test results.

`amount_due = patient(1).billing`
```amount_due = 127 ```
```bar(patient(1).test) title(['Test Results for ', patient(1).name])```

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