Python 2.7如果middle_name爲null打印其他東西打印其他東西

Question

我正在嘗試構建一個在線MASH遊戲。我如何輸出：

打印「歡迎來到節目{} {}」格式（self.first_name，self.last_name）如果沒有輸入中間名，但：

打印「歡迎來到節目{ } {} {}」格式（self.first_name，self.middle_name，self.last_name）如果輸入中間名：

類名稱（對象）：

def __init__(self, first_name='', last_name='', middle_name=''): 
    if not first_name: 
     first_name = raw_input("What is your first name: ") 
    if not last_name: 
     last_name = raw_input("What is your last name: ") 
    if not middle_name: 
     middle_name = raw_input("What is your middle name[Leave blank if not applicable]: ") 
     if middle_name == '': 
      print "No middle name here!" 
    self.first_name = first_name 
    self.last_name = last_name 
    self.middle_name = middle_name 
    self.print_name() 

def print_name(self): 
    if not middle_name: 
     print "Welcome to the program {} {}".format(self.first_name, self.last_name) 
    else: 
     print "Welcome to the program {} {} {}".format(self.first_name, 
                self.middle_name, 
                self.last_name) 

克里斯=名稱（）

Answer 1

這似乎s到是您所描述的行爲：

class Name (object): 

    def __init__(self, first_name, last_name, middle_name=None): 
     self.first_name = first_name 
     self.last_name = last_name 
     self.middle_name = middle_name 
     self.print_name() 

    def print_name(self): 
     if not self.middle_name: 
      print "Welcome to the program {} {}".format(self.first_name, self.last_name) 
     else: 
      print "Welcome to the program {} {} {}".format(self.first_name, self.middle_name, self.last_name) 

chris_jones = Name(first_name='Chris', last_name='Jones') 
chris_taylor_jones = Name(first_name='Chris', middle_name='Taylor', last_name='Jones') 

通知我只加了None參數你__init__()方法。 middle_name=None提供默認值，以防調用方不提供參數middle_name。 This syntactic feature is called a "keyword argument"。

輸出：

Welcome to the program Chris Jones 
Welcome to the program Chris Taylor Jones