---
title: Random
---

Pseudo-random number generation.

<details disabled>
<summary tabindex="-1">Added in <code>0.5.0</code></summary>
No other changes yet.
</details>

```grain
from "random" include Random
```

## Types

Type declarations included in the Random module.

### Random.**Random**

```grain
type Random
```

## Values

Functions and constants included in the Random module.

### Random.**make**

<details disabled>
<summary tabindex="-1">Added in <code>0.5.0</code></summary>
No other changes yet.
</details>

```grain
make: (seed: Uint64) => Random
```

Creates a new pseudo-random number generator with the given seed.

Parameters:

| param  | type     | description                                     |
| ------ | -------- | ----------------------------------------------- |
| `seed` | `Uint64` | The seed for the pseudo-random number generator |

Returns:

| type     | description                        |
| -------- | ---------------------------------- |
| `Random` | The pseudo-random number generator |

### Random.**makeUnseeded**

<details disabled>
<summary tabindex="-1">Added in <code>0.5.0</code></summary>
No other changes yet.
</details>

```grain
makeUnseeded: () => Result<Random, Exception>
```

Creates a new pseudo-random number generator with a random seed.

Returns:

| type                        | description                                                                                     |
| --------------------------- | ----------------------------------------------------------------------------------------------- |
| `Result<Random, Exception>` | `Ok(generator)` of a pseudo-random number generator if successful or `Err(exception)` otherwise |

### Random.**nextUint32**

<details>
<summary>Added in <code>0.6.0</code></summary>
<table>
<thead>
<tr><th>version</th><th>changes</th></tr>
</thead>
<tbody>
<tr><td><code>0.5.0</code></td><td>Originally named `nextInt32`</td></tr>
</tbody>
</table>
</details>

```grain
nextUint32: (random: Random) => Uint32
```

Generates a random 32-bit integer from the given pseudo-random number generator.

Parameters:

| param    | type     | description                               |
| -------- | -------- | ----------------------------------------- |
| `random` | `Random` | The pseudo-random number generator to use |

Returns:

| type     | description                   |
| -------- | ----------------------------- |
| `Uint32` | The randomly generated number |

### Random.**nextUint64**

<details>
<summary>Added in <code>0.6.0</code></summary>
<table>
<thead>
<tr><th>version</th><th>changes</th></tr>
</thead>
<tbody>
<tr><td><code>0.5.0</code></td><td>Originally named `nextInt64`</td></tr>
</tbody>
</table>
</details>

```grain
nextUint64: (random: Random) => Uint64
```

Generates a random 64-bit integer from the given pseudo-random number generator.

Parameters:

| param    | type     | description                               |
| -------- | -------- | ----------------------------------------- |
| `random` | `Random` | The pseudo-random number generator to use |

Returns:

| type     | description                   |
| -------- | ----------------------------- |
| `Uint64` | The randomly generated number |

### Random.**nextUint32InRange**

<details>
<summary>Added in <code>0.6.0</code></summary>
<table>
<thead>
<tr><th>version</th><th>changes</th></tr>
</thead>
<tbody>
<tr><td><code>0.5.0</code></td><td>Originally named `nextInt32InRange`</td></tr>
</tbody>
</table>
</details>

```grain
nextUint32InRange: (random: Random, low: Uint32, high: Uint32) => Uint32
```

Generates a random 32-bit integer from the given pseudo-random number generator
from a uniform distribution in the given range.

Parameters:

| param    | type     | description                               |
| -------- | -------- | ----------------------------------------- |
| `random` | `Random` | The pseudo-random number generator to use |
| `low`    | `Uint32` | The lower bound of the range (inclusive)  |
| `high`   | `Uint32` | The upper bound of the range (exclusive)  |

Returns:

| type     | description                   |
| -------- | ----------------------------- |
| `Uint32` | The randomly generated number |

### Random.**nextUint64InRange**

<details>
<summary>Added in <code>0.6.0</code></summary>
<table>
<thead>
<tr><th>version</th><th>changes</th></tr>
</thead>
<tbody>
<tr><td><code>0.5.0</code></td><td>Originally named `nextInt64InRange`</td></tr>
</tbody>
</table>
</details>

```grain
nextUint64InRange: (random: Random, low: Uint64, high: Uint64) => Uint64
```

Generates a random 64-bit integer from the given pseudo-random number generator
from a uniform distribution in the given range.

Parameters:

| param    | type     | description                               |
| -------- | -------- | ----------------------------------------- |
| `random` | `Random` | The pseudo-random number generator to use |
| `low`    | `Uint64` | The lower bound of the range (inclusive)  |
| `high`   | `Uint64` | The upper bound of the range (exclusive)  |

Returns:

| type     | description                   |
| -------- | ----------------------------- |
| `Uint64` | The randomly generated number |