> ## Documentation Index
> Fetch the complete documentation index at: https://axiom.co/docs/llms.txt
> Use this file to discover all available pages before exploring further.

<AgentInstructions>

## Submitting Feedback

If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback:

POST https://axiom.co/docs/feedback

```json
{
  "path": "/apl/scalar-functions/conversion-functions/tobool",
  "feedback": "Description of the issue"
}
```

Only submit feedback when you have something specific and actionable to report.

</AgentInstructions>

# tobool

> This page explains how to use the tobool function in APL.

Use the `tobool` function to convert various data types to a boolean value. This is helpful when you need to normalize values from different sources into boolean format for conditional logic, filtering, or boolean operations.

You typically use `tobool` when working with data that represents boolean values as strings (like "true"/"false" or "1"/"0"), numbers, or other types that need to be converted to proper boolean values.

## For users of other query languages

If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL.

<AccordionGroup>
  <Accordion title="Splunk SPL users">
    In Splunk, you use `if` expressions or `tonumber` with comparisons to convert values to boolean-like results. In APL, `tobool` provides a direct conversion function that handles various input types.

    <CodeGroup>
      ```sql Splunk example theme={null}
      ... | eval is_active = if(field == "true" OR field == 1, 1, 0)
      ```

      ```kusto APL equivalent theme={null}
      ... | extend is_active = tobool(field)
      ```
    </CodeGroup>
  </Accordion>

  <Accordion title="ANSI SQL users">
    In standard SQL, you use `CASE` statements or `CAST` to convert values to boolean. In APL, `tobool` provides a simpler way to convert various types to boolean values.

    <CodeGroup>
      ```sql SQL example theme={null}
      SELECT CASE WHEN status = 'active' THEN TRUE ELSE FALSE END AS is_active FROM logs;
      ```

      ```kusto APL equivalent theme={null}
      ['sample-http-logs']
      | extend is_active = tobool(is_active)
      ```
    </CodeGroup>
  </Accordion>
</AccordionGroup>

## Usage

### Syntax

```kusto theme={null}
tobool(value)
```

### Parameters

| Name  | Type    | Description                      |
| ----- | ------- | -------------------------------- |
| value | dynamic | The value to convert to boolean. |

### Returns

If conversion is successful, the result is a boolean. If conversion isn’t successful, the result is `false`.

### Conversion behavior

The `tobool` function converts values based on their type:

* **Boolean**: Returns the value unchanged.
* **Integer/Float/Duration**: Returns `true` if the value is not equal to 0, otherwise `false`.
* **Datetime**: Returns `true` if the value is anything other than epoch (zero time), otherwise `false`.
* **String**: Returns `true` if the value equals `"1"`, `"t"`, `"T"`, `"TRUE"`, `"true"`, or `"True"`. Returns `false` if the value equals `"0"`, `"f"`, `"F"`, `"FALSE"`, `"false"`, or `"False"`. Returns `null` for any other string value.

## Example

Convert string representations of Boolean values to actual Boolean types for filtering and analysis.

**Query**

```kusto theme={null}
['sample-http-logs']
| extend is_active = tobool(is_active)
| extend is_enabled = tobool(enabled)
| where is_active == true or is_enabled == true
| project _time, uri, status, is_active, enabled, is_active, is_enabled
```

**Output**

| \_time           | uri        | status | is\_active | enabled | is\_active | is\_enabled |
| ---------------- | ---------- | ------ | ---------- | ------- | ---------- | ----------- |
| Jun 24, 09:28:10 | /api/users | 200    | "true"     | "1"     | true       | true        |

This example converts string representations of boolean values (like `"true"` and `"1"`) to actual boolean types, enabling proper boolean logic and filtering.

## List of related functions

* [isbool](/apl/scalar-functions/conversion-functions/isbool): Checks if a value is a boolean. Use `isbool` to validate types, and `tobool` to convert values to boolean.
* [case](/apl/scalar-functions/conditional-function#case): Evaluates conditions and returns values. Use `case` for complex conditional logic, and `tobool` for simple conversions.
* [iff](/apl/scalar-functions/conditional-function#iff): Returns one of two values based on a predicate. Use `iff` for conditional assignment, and `tobool` for type conversion.