How can I check if a string has numbers (0-9) and dashes? The user will type a phone number, but I want to make sure he doesn't enter letters, just numbers and dashes. I already wrote code to make sure it is the right size (12 characters) and the dashes are in the right order, but I want to restrict the string to have no letters. Thank you!!! def updateMessages(self, parameters): """Modify the messages created by internal validation for each tool parameter. This method is called after internal validation.""" Status = parameters[0] #this can only be included if the field is not optional: Phone = parameters[12] if Phone.value: Phonetxt = Phone.value if len(Phonetxt) < 12: Phone.setErrorMessage("Make sure the phone number is in this format: ex: 979-458-6630") if len(Phonetxt) > 12: Phone.setErrorMessage("Make sure the phone number is in this format: ex: 979-458-6630") if not "-" in Phonetxt: Phone.setErrorMessage("Make sure the phone number is in this format: ex: 979-458-6630") if len(Phonetxt) == 12: phone3dig = Phonetxt[0:4] if not "-" in phone3dig: Phone.setErrorMessage("Make sure the phone number is in this format: ex: 979-458-6630") phone32dig = Phonetxt[0:3] if "-" in phone32dig: Phone.setErrorMessage("Make sure the phone number is in this format: ex: 979-458-6630") phone6dig = Phonetxt[4:8] if not "-" in phone6dig: Phone.setErrorMessage("Make sure the phone number is in this format: ex: 979-458-6630") phone62dig = Phonetxt[4:7] if "-" in phone62dig: Phone.setErrorMessage("Make sure the phone number is in this format: ex: 979-458-6630") phone12dig = Phonetxt[8:] if "-" in phone12dig: Phone.setErrorMessage("Make sure the phone number is in this format: ex: 979-458-6630")