Returns the index value of the first character in a specified substring that occurs in a given string.UnitSystemCategorystring handling routinesfunction Pos(Substr: string; S: string): Integer;DescriptionPos searches for a substring, Substr, in a string, S. Substr and S are string-type expressions.Pos searches for Substr within S and returns an integer value that is the index of the first character of Substr within S. Pos is case-sensitive. If Substr is not found, Pos returns zero.
pos返回一个整数,如果找到了字符串,会返回字符串所在的位置,反之会返回0