## ISA Test Type of Variable

Section: Inspection Functions

### Usage

Tests the type of a variable. The syntax for its use is

       y = isa(x,type)

where `x` is the variable to test, and `type` is the type. Supported built-in types are

- `'cell'` for cell-arrays
- `'struct'` for structure-arrays
- `'logical'` for logical arrays
- `'uint8'` for unsigned 8-bit integers
- `'int8'` for signed 8-bit integers
- `'uint16'` for unsigned 16-bit integers
- `'int16'` for signed 16-bit integers
- `'uint32'` for unsigned 32-bit integers
- `'int32'` for signed 32-bit integers
- `'uint64'` for unsigned 64-bit integers
- `'int64'` for signed 64-bit integers
- `'single'` for 32-bit floating point numbers
- `'double'` for 64-bit floating point numbers
- `'char'` for string arrays

If the argument is a user-defined type (via the `class` function), then the name of that class is returned.

### Examples

Here are some examples of the `isa` call.

    --> a = {1}

    a =
     [1]

    --> isa(a,'char')

    ans =
     0

    --> isa(a,'cell')

    ans =
     1

Here we use `isa` along with shortcut boolean evaluation to safely determine if a variable contains the string `'hello'`

    --> a = 'hello'

    a =
    hello
    --> isa(a,'char') && strcmp(a,'hello')

    ans =
     1