#### IsDate

##### IsDate(number or string)

Returns true if the given String or Number value can be converted to a valid Date and returns false otherwise. A valid Date is any Date between 100-1-1 and 9999-12-31.

Parameters

- number - A Number value representing the number of days starting from January 1, 1900. It can be positive or negative, and is truncated if fractional.
- string - A text string representing a date and many forms can be accepted. If the string is a right Date value and format, the function returns true, otherwise false.

Return value

Boolean value, True or False.

Examples

- `IsDate(50)` - Returns true since the number 50 is interpreted as 50 days from Jan. 1, 1900, which is Feb 19, 1900.
- `IsDate(-50)` - Returns true since the number –50 is interpreted as 50 days before Jan 1, 1900, which is Nov 11, 1899.
- `IsDate("Feb 1, 2004")` - Returns true since the string is a right Date value and there is only one blank between 'Feb' and '1,' and '2004'.
- `IsDate("2004 - 2 - 19")` - Returns false since the String format is not right Date format.
- `IsDate("2003/2/29")` - Returns false since 2003 is not leap year.
- `IsDate("2004*2*19")` - Returns false since the String format is not right Date format.