tobool

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.

Usage

Syntax

tobool(value)

Parameters

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 isn't 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

['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

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: Checks if a value is a boolean. Use isbool to validate types, and tobool to convert values to boolean.
• case: Evaluates conditions and returns values. Use case for complex conditional logic, and tobool for simple conversions.
• iff: Returns one of two values based on a predicate. Use iff for conditional assignment, and tobool for type conversion.

Other query languages