isreal
This page explains how to use the isreal function in APL.
Use the isreal function to determine whether a value is a real number. This function is helpful when you need to validate data before performing numeric operations. For example, you can use isreal to filter out invalid values which could otherwise disrupt aggregations or calculations.
You often use isreal in data cleaning pipelines, conditional logic, and when inspecting metrics like durations, latencies, or numeric identifiers. It’s especially useful when working with telemetry or log data that includes optional or incomplete numeric fields.
Usage
Syntax
isreal(value)Parameters
| Name | Type | Description |
|---|---|---|
| value | any | The input value to evaluate. |
Returns
Returns true if the input is a valid real number. Returns false for strings, nulls, or non-numeric types.
Example
Use isreal to identify real number values.
Query
['sample-http-logs']
| extend is_real = isreal(123.11)Output
| _time | is_real |
|---|---|
| 2025-06-05T12:01:00Z | true |
List of related functions
- isimei: Checks whether a value is a valid International Mobile Equipment Identity (IMEI) number.
- ismap: Checks whether a value is of the
dynamictype and represents a mapping. - iscc: Checks whether a value is a valid credit card (CC) number.
- isstring: Checks whether a value is a string. Use this for scalar string validation.
- isutf8: Checks whether a value is a valid UTF-8 encoded sequence.