将 if-elseif 语句变成字典

Question

我有以下代码用于对服务器进行 RESTful 调用：

def request(self, request, account_id, user):

    if request is 'get_id':
        #Get user from id
        result = requests.get(api_root + "/accounts/" + account_id + "/users/" + user, headers=self.headers)

    elif request is 'get_username':
        #Get user from username
        result = requests.get(api_root + "/accounts/" + account_id + "/users?username=" + user, headers=self.headers)

    elif request is 'get_email':
        #Get user from username
        result = requests.get(api_root + "/accounts/" + account_id + "/users?email=" + user, headers=self.headers)

    elif request is 'post':
        #Add user to new account
        result = requests.post(api_root + '/accounts/' + account_id + '/users', data=json.dumps(user), headers=self.headers)

    elif request is 'delete':
        #Delete user from account
        result = requests.delete(api_root + "/accounts/" + account_id + "/users/" + user, headers=self.headers)

    #Throw exception if non-200 response
    result.raise_for_status()

    #Print request result / status
    print "\nRequest " + request + " Result: " + result.text + "\nStatus: " + str(result.status_code)

    return result

我知道这很难看，我想把它改成字典，比如：

def request(self, request, account_id, user):
    url = api_root + "/accounts/" + account_id

    function_dictionary = {}
    function_dictionary['get_id']       = requests.get(url + "/users/" + user, headers=self.headers)
    function_dictionary['get_username'] = requests.get(api_root + "/accounts/" + account_id + "/users?username=" + user, headers=self.headers)
    function_dictionary['get_email']    = requests.get(api_root + "/accounts/" + account_id + "/users?email=" + user, headers=self.headers)
    function_dictionary['delete']       = requests.delete(url + "/users/" + user, headers=self.headers)
    function_dictionary['post']         = requests.post(url + '/users', data=json.dumps(user), headers=self.headers)  

    result = function_dictionary.get(request)

    #Throw exception if non-200 response
    result.raise_for_status()
    return result

我仍然觉得我走错了路。谁能告诉我在 Python 中处理 if / elseif 语句的正确方法是什么？

谢谢！

Answer 1

使用dict 替换if: elif: 循环肯定是Pythonic，但请注意，在您的示例中，您调用 requests.get 等存储在字典中的每个案例，即字典值是这些调用的结果。

另一种方法是将函数和参数分别存储在字典中：

function_dict = {'get_id': (requests.get, # function
                            (url + "/users/" + user,), # tuple of arguments  
                            {'headers': self.headers}), # dict of keyword args
                 ...}

现在你可以使用了

func, args, kwargs = function_dict[request]
result = func(*args, **kwargs)

另外，请注意使用is 比较字符串是一个坏主意（尽管它是sometimes works）；最好使用==:

if request == 'get_id':