KeepChar - script and chart function

KeepChar() returns a string consisting of the first string ,'text', less any of the characters NOT contained in the second string, "keep_chars".

Syntax:  

KeepChar(text, keep_chars)

Return data type: string

Arguments:  

Examples and results:

Example	Result
KeepChar ( 'a1b2c3','123' )	Returns '123'.
KeepChar ( 'a1b2c3','1234' )	Returns '123'.
KeepChar ( 'a1b22c3','1234' )	Returns '1223'.
KeepChar ( 'a1b2c3','312' )	Returns '123'.