# CheckNumberOrExpression method

Checks if:

* A given expression is valid.
* A number is correct according to the locale.

## Parameters

| Name | Description | Mandatory | Type |
| --- | --- | --- | --- |
| qExpr | Expression to check. | Yes | String |

## Returns

| Name | Description | Type |
| --- | --- | --- |
| qErrorMsg | Message displayed when there is a syntax error. | String |
| qBadFieldNames | A list of bad field names. | Array of [NxRange](https://help.qlik.com/en-US/sense-developer/May2026/Subsystems/EngineJSONAPI/Content/models-nxrange.htm) |