---
url: /flow/guide/scripting-reference/functions/numeric/isnumber.md
---

# IsNumber

## Declaration

`Function IsNumber( const S : string) : Boolean`

### Example

```pascal
procedure OnMapEvent(var Value:Variant);
begin
  Value := IsNumber('abc123'); //returns false
Value := IsNumber('123'); //returns true.
Value := IsNumber('$123.00'); //returns false.
end;
```

## Description

Returns True or False depending on whether the input string contains only numeric characters or not. If this function returns True then you can safely use a [Conversion](/flow/guide/scripting-reference/functions/conversion/) function on it to turn it into a numeric data type.

Refer [IsDigit](/flow/guide/scripting-reference/functions/numeric/isdigit) for a function that checks only the first character to see if it is a digit. Refer to [IsCurrencyNumber](/flow/guide/scripting-reference/functions/numeric/iscurrencynumber) for a function that checks if the string contains a number in currency format. This function allows currency format symbols like $,.