优化创建列表字典

Question

I have a following class

class Test:
    self.value = 0
    self.name = ''

I have million of records and i want to sort only selective records based on their name . I have created a separate list called whitelist_names . The way i am making the dictionary-list object is like that

'''input_value and input_name are being feed from a file-read'''
map_list = {}

t = Test(input_value, input_name)

if t.input_name in whitelist_names:
    name_list = []
    if t.input_name in map_list:
        name_list = map_list[t.input_name]
    name_list.append(t)
    map_list[t.input_name] = name_list

The above piece of code is taking forever. I am new to python so just wanted to make sure if i am doing it right or not.

Answer 1

Well as you're checking if a certain name is in a list it is quite logical that its taking a while. If the white listed names are all unique you could use a set instead of a list. Set comprehension is a lot faster than list.

Furthermore, instead of implementing a class to hold a name and the amount of times it showed up, I would suggest you use a dictionary. As dictionaries are implemented as hashmaps the check if the entry exist is very fast.