python从文件中读取数据并计算结果

Question

i want to store some values in a python file like blew here is my abc.py file

{
  21:"This field is required",
  22:"Value can't be null",
  23:"other custom message",
}

then i want to calculate code from a given string in a python function. example:

def calculate_code(error_message):
    #process error_message and read data from abc.py file
    #calculate error_code
    return eror_code

like if i have error_message = "Value can't be null" then i ll get error_code = 22.

what is the best way to do it?

Answer 1

A sensible solution would be to define a cache class (based on a dictionary) from messages to error codes. This is not a complete solution, but this provides a skeleton:

from datetime import datetime from os import stat import time

class Cache(object):
    def __init__(self, filename):
        self._filename = filename
        self._populate_cache()

    def __getitem__(self, name):
        if self._check_file_updated():
           self._populate_cache()
        return self._cache[name]

    def _populate_cache(self):
        self._populate_time = time.mktime(datetime.now().timetuple())
        self._cache = read_file_as_dict(self._filename)
        print "debug: updated cache"

    def _check_file_updated(self):
        return stat(self._filename).st_mtime > self._populate_time


def read_file_as_dict(filename):
    # needs an implementation: just simulating
    return { "Blown up": 25, "Warning": 31 }

Usage:

cache = Cache("test")
>>> cache["Blown up"]
25
>>> cache["Blown up"]
25

Now I touch the "test" file:

>>> cache["Blown up"]
debug: updated cache
25