|                       |                                                                                                                                                 |
| --------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------- |
| **_Description:_**    | An anonymous function, often called a lambda function, which accepts parameters and _closes over_ (i.e., uses) variables from outside its scope |
| **_Annotation:_**     | `closure`                                                                                                                                       |
| **_Literal Syntax:_** | `{\|args\| expressions }`                                                                                                                       |
| **_See also:_**       | [Language Reference - Closure](/lang-guide/chapters/types/basic_types/closure.md)                                                               |

Simple example:

This closure returns a boolean result of the comparison and then uses it in a `filter` command to return all values greater than 5.

```nu
let compare_closure = {|a| $a > 5 }
let original_list = [ 40 -4 0 8 12 16 -16 ]
$original_list | filter $compare_closure
# => ╭───┬────╮
# => │ 0 │ 40 │
# => │ 1 │  8 │
# => │ 2 │ 12 │
# => │ 3 │ 16 │
# => ╰───┴────╯
```

Closures are a useful way to represent code that can be executed on each row of data via [filters](/lang-guide/chapters/filters/00_filters_overview.md)

### Binary data

|                       |                                                                             |
| --------------------- | --------------------------------------------------------------------------- |
| **_Description:_**    | Represents binary data                                                      |
| **_Annotation:_**     | `binary`                                                                    |
| **_Literal Syntax:_** | `0x[ffffffff]` - hex-based binary representation                            |
|                       | `0o[1234567]` - octal-based binary representation                           |
|                       | `0b[10101010101]` - binary-based binary representation                      |
| **_See also:_**       | [Language Guide - Binary](/lang-guide/chapters/types/basic_types/binary.md) |

Binary data, like the data from an image file, is a group of raw bytes.

Simple example - Confirm that a JPEG file starts with the proper identifier:

```nu
open nushell_logo.jpg
| into binary
| first 2
| $in == 0x[ff d8]
# => true
```

## Structured Data Types

Nushell includes a collection of structured data types that can contain the primitive types above. For example, instead of a single `float`, structured data gives us a way to represent multiple `float` values, such as a `list` of temperature readings, in the same value. Nushell supports the following structured data types:

### Lists

|                       |                                                                                 |
| --------------------- | ------------------------------------------------------------------------------- |
| **_Description:_**    | Ordered sequence of zero or more values of any type                             |
| **_Annotation:_**     | `list`                                                                          |
| **_Literal Syntax:_** | See [Language Guide - List](/lang-guide/chapters/types/basic_types/list.md)     |
| **_See Also:_**       | [Working with Lists](./working_with_lists.md)                                   |
|                       | [Navigating and Accessing Structured Data](/book/navigating_structured_data.md) |

Simple example:

```nu
[Sam Fred George]
# => ╭───┬────────╮
# => │ 0 │ Sam    │
# => │ 1 │ Fred   │
# => │ 2 │ George │
# => ╰───┴────────╯
```

### Records

|                       |                                                                                 |