VERIFY function

Purpose | Determine whether each character of a string is present in another string.
Syntax | x = VERIFY([start&,] MainString, MatchString)

Remarks

VERIFY returns zero if each character in MainString is present in MatchString. If not, it returns the position of the first non-matching character in MainString.

This function is very useful for determining if a string contains only numeric digits, for example.

VERIFY is case-sensitive, so capitalization matters.

Restrictions | If start& evaluates to a position outside of the string on either side, or if start& is zero, VERIFY returns zero.
See also | INSTR, LCASE$, LTRIM$, MID$, REMOVE$, REPLACE, RIGHT$, RTRIM$, TALLY, TRIM$, UCASE$
Example | ' returns 4 since "." is not in "0123456789" x& = VERIFY("123.65,22.5", "0123456789") ' returns 7 since 5 starts it past the first non-digit ("." at position 4) x& = VERIFY(5,"123.65,22.5", "0123456789")