字典僅在 for 循環中添加最后一個鍵值對

Question

我有一個 for 循環，它遍歷城市列表並為每個城市分配一個total_city_value 。 我正在嘗試將在 for 循環期間創建的每個唯一的 total_city_value 添加到字典中，但是當我打印字典時，它似乎只是將最終的 total_city_value 保留在 for 循環中。

            for broad_variable in broad_variable_list:
                    
                    # check if the current broad variable is equal to the first broad variable the user chose
                    if broad_variable == broad_variable1:
                        
                        # if the city's specific variable is equal to the specific variable the user chose get the value of it based on it's ranking weight
                        if City.objects.values_list(broad_variable, flat=True).filter(city=cities).first() == specific_variable1:
                            city_variable1_value = 1 * weight_variable1
                            #print("city_variable1_value",city_variable1_value)
                        
                        # else assign a value of 0
                        else:
                            city_variable1_value = 0
                    
                    # check if the current broad variable is equal to the second broad variable the user chose
                    if broad_variable == broad_variable2:
                        
                        # if the city's specific variable is equal to the specific variable the user chose get the value of it based on it's ranking weight
                        if City.objects.values_list(broad_variable, flat=True).filter(city=cities).first() == specific_variable2:
                            city_variable2_value = 1 * weight_variable2
                        
                        # else assign a value of 0
                        else:
                            city_variable2_value = 0
                    
                total_city_value = city_variable1_value + city_variable2_value
                city_value_dictionary[cities] = total_city_value
            
            print(city_value_dictionary)

Answer 1

也許它很簡單：

city_value_dictionary[cities] += total_city_value

將新值添加到現有值？ 您可能需要檢查這是否是該cities值的第一次，因為第一次不會添加條目。 一些老生常談的東西：

try:
    city_value_dictionary[cities] += total_city_value
except KeyError:
    city_value_dictionary[cities] = total_city_value

或者：

total = city_value_dictionary.get(cities, 0)
city_value_dictionary[cities] = total + total_city_value