Python 更新别名和父级

Question

我必须在 Python 中创建一个电话簿，它应该具有以下功能：

add name number - 添加 number 和 name 到字典。名称必须是唯一的，对于数字也是如此。
lookup name – 打印与name
alias name newname – 允许从 newname[=44 搜索 name =]
更改姓名号码 – 将与现有姓名关联的号码更改为号码
quit – 退出程序

运行程序应如下所示：

telebok> add peter.forsberg 12345
telebok> lookup peter.forsberg
12345
telebok> alias peter.forsberg foppa
telebok> lookup foppa
12345
telebok> alias foppa MR21
telebok> change MR21 67890
telebok> lookup peter.forsberg
67890

除了零钱，我一切正常：

def adressbook():
telebook = {"jacob.engert":"8472923777", "nisse":"092563243"}
while True:
    book = raw_input("telebook> ").lower()
    lista = book.split()
    if "add" in lista[0]:
        n = lista[1]
        x = lista[2]
        if x in telebook.values():
            print "Number already exists!"
        elif n in telebook:
            print "Name already exists!"
        else:
            telebook[n] = x
            print telebook
    elif "lookup" in lista[0]:
        n = lista[1]
        if n in telebook:
            print n, "", telebook[n]
        elif n.isdigit():
            print "Type only characters!"
        else:
            print "This person does not exist!"
    elif "alias" in lista[0]:
        n = lista[1]
        alias = lista[2]
        if n in telebook:
            v = telebook.get(n)
            telebook[alias] = v 

    elif "change" in lista[0]:
        key = lista[1]
        value = telebook.get(key)
        newvalue = lista[2]
        for key, value in telebook.items():
            telebook.update({key:newvalue})
            print telebook

所以当我更新别名时，我希望原件也更新，但我得到了这个结果：

>>> adressbook()
telebook> add ove 345347657
{'jacob.engert': '8472923777', 'ove': '345347657', 'nisse': '092563243'}
telebook> alias ove mr.o
telebook> lookup mr.o
mr.o  345347657
telebook> change mr.o 534523234
{'mr.o': '534523234', 'jacob.engert': '8472923777', 'ove': '345347657',   nisse': '092563243'}
{'mr.o': '534523234', 'jacob.engert': '534523234', 'ove': '345347657', 'nisse': '092563243'}
{'mr.o': '534523234', 'jacob.engert': '534523234', 'ove': '534523234', 'nisse': '092563243'}
{'mr.o': '534523234', 'jacob.engert': '534523234', 'ove': '534523234', 'nisse': '534523234'}
telebook>

所以我的问题是，我怎样才能做到当我改变别名的号码时，原来的号码也会改变？

Answer 1

你几乎走在了正确的轨道上。

为了更改所有条目（别名和父项），您需要查找与用户要更改的条目（无论是否为别名）具有相同编号的条目并替换它们的编号使用新的：

key = lista[1]
newvalue = lista[2]
present_value = telebook.get(key)
if present_value:
    for name, num in telebook.items():
        if num == present_value:
            telebook[name] = newvalue

或使用字典理解：

key = lista[1]
newvalue = lista[2]
present_value = telebook.get(key)
if present_value:
    upd = {name: newvalue for name, num in telebook.items() if num == present_value }
    telebook.update(upd)

或使用 generator expression 生成元组序列（dict.update 两者都接受）

key = lista[1]
newvalue = lista[2]
present_value = telebook.get(key)
if present_value:
    upd = ((name, newvalue) for name, num in telebook.items() if num == present_value)
    telebook.update(upd)

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