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# double

Double-precision arrays

## Description

By default, MATLAB® stores all numeric variables as double-precision floating-point values that are 8 bytes (64 bits). These variables have data type (class) `double`. For example:

```x = 10; whos x```
``` Name Size Bytes Class Attributes x 1x1 8 double ```

For more information on floating-point values, see Floating-Point Numbers.

## Creation

You can create a double-precision array using the `[]` operator, such as `A = [1 2 3; 4 5 6]`. In addition, many functions return double-precision arrays, such as `sin`.

If you have an array of a different type, such as `single` or `int8`, then you can convert that array to double precision using the `double` function.

### Syntax

``Y = double(X)``

### Description

example

````Y = double(X)` converts the values in `X` to double precision.```

### Input Arguments

expand all

Input array, specified as a scalar, vector, matrix, or multidimensional array.

Data Types: `single` | `int8` | `int16` | `int32` | `int64` | `uint8` | `uint16` | `uint32` | `uint64` | `logical` | `char` | `string`

## Examples

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By default, numbers in MATLAB are of the data type `double`. You can use the `class` function to verify a variable's type.

```x = 100; xtype = class(x)```
```xtype = 'double' ```

Use the `double` function to convert variables that are not double precision to type `double`.

`y = true`
```y = logical 1 ```
```ydouble = double(y); ynewtype = class(ydouble)```
```ynewtype = 'double' ```

## Tips

• When you are creating a class, overload `double` when it makes sense to convert an object of that class to a double-precision value.