python循环一次释放内存_循环期间释放内存

我的代码内存有问题。我的解析器可以这样总结：# coding=utf-8

#! /usr/bin/env python

import sys

import json

from collections import defaultdict

class MyParserIter(object):

def _parse_line(self, line):

for couple in line.split(","):

key, value = couple.split(':')[0], couple.split(':')[1]

self.__hash[key].append(value)

def __init__(self, line):

# not the real parsing just a example to parse each

# line to a dict-like obj

self.__hash = defaultdict(list)

self._parse_line(line)

def __iter__(self):

return iter(self.__hash.values())

def to_dict(self):

return self.__hash

def __getitem__(self, item):

return self.__hash[item]

def free(self, item):

self.__hash[item] = None

def free_all(self):

for k in self.__hash:

self.free(k)

def to_json(self):

return json.dumps(self.to_dict())

def parse_file(file_path):

list_result = []

with open(file_path) as fin:

for line in fin:

parsed_line_obj = MyParserIter(line)

list_result.append(parsed_line_obj)

return list_result

def write_to_file(list_obj):

with open("out.out", "w") as fout:

for obj in list_obj:

json_out = obj.to_json()

fout.write(json_out + "\n")

obj.free_all()

obj = None

if __name__ == '__main__':

result_list = parse_file('test.in')

print(sys.getsizeof(result_list))

write_to_file(result_list)

print(sys.getsizeof(result_list))

# the same result for memory usage result_list

print(sys.getsizeof([None] * len(result_list)))

# the result is not the same :(

其目的是解析(大)文件，每一行都转换成一个json对象，并将其写回一个文件。

我的目标是减少内存占用，因为在某些情况下，此代码会引发内存错误。每次fout.write之后，我想删除(空闲内存)obj引用。

我试图将obj设置为不调用方法obj.free_all()，但它们都没有释放内存。我还使用了simplejson而不是json，这减少了内存占用，但在某些情况下仍然太大。

test.in看起来像：test1:OK,test3:OK,...

test1:OK,test3:OK,...

test1:OK,test3:OK,test4:test_again...

....