> ## Documentation Index
> Fetch the complete documentation index at: https://axiom-mano-sample-app.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Pair functions

> Learn how to use and combine different pair functions in APL

## Pair functions

| **Function Name**            | **Description**                      |
| ---------------------------- | ------------------------------------ |
| [pair()](#pair)              | Creates a pair from a key and value. |
| [parse\_pair()](#parse-pair) | Parses a string to form a pair.      |

Each argument has a **required** section which is denoted with `required` or `optional`

* If it’s denoted by `required` it means the argument must be passed into that function before it'll work.
* if it’s denoted by `optional` it means the function can work without passing the argument value.

## pair()

Creates a pair from a key and value.

### Arguments

| **Name**  | **Type** | **Required or Optional** | **Description**                                 |
| --------- | -------- | ------------------------ | ----------------------------------------------- |
| Key       | string   | Required                 | String for the key in the pair                  |
| Value     | string   | Required                 | String for the value in the pair                |
| Separator | string   | Optional (Default: ":")  | Separator between the key and value in the pair |

### Returns

Returns a pair with the key **Key** and the value **Value** with the separator **Seperator**.

### Examples

```kusto
pair("key", "value", ".")
```

```kusto
['logs']
| where tags contains pair("host", "mymachine")
```

[Run in Playground]()

## parse\_pair()

Creates a pair from a key and value.

### Arguments

| **Name**  | **Type** | **Required or Optional** | **Description**                                 |
| --------- | -------- | ------------------------ | ----------------------------------------------- |
| Pair      | string   | Required                 | String that has a pair of key value to pull out |
| Separator | string   | Optional (Default: ":")  | Separator between the key and value in the pair |

### Returns

Returns a pair with the key and value separated by the separator **Seperator** in **Pair**. If
none is found a pair with the value of **Pair** and an empty key is returned.

### Examples

```kusto
parse_pair("key.value", ".")
```

```kusto
['logs']
| where parse_pair(tags[0]).key == "host"
```

[Run in Playground]()