I have the following pattern='^([0-9]{0,%s})(\.[0-9]{0,%s})?$' % (self.IntegerWidth, self.DecimalWidth) ) if re.match(pattern, self.GetValue())==None: self.BackColor == "pink" else: self.BackColor == "white" self.IntegerWidth = 2 self.DecimalWidth=2 the problem is the pattern allows ".999". What am I doing wrong? -- John Fabiani