【发布时间】:2026-02-08 07:00:01
【问题描述】:
import time
import logging
from functools import reduce
logging.basicConfig(filename='debug.log', level=logging.DEBUG)
def read_large_file(file_object):
"""Uses a generator to read a large file lazily"""
while True:
data = file_object.readline()
if not data:
break
yield data
def process_file_1(file_path):
"""Opens a large file and reads it in"""
try:
with open(file_path) as fp:
for line in read_large_file(fp):
logging.debug(line)
pass
except(IOError, OSError):
print('Error Opening or Processing file')
def process_file_2(file_path):
"""Opens a large file and reads it in"""
try:
with open(path) as file_handler:
while True:
logging.debug(next(file_handler))
except (IOError, OSError):
print("Error opening / processing file")
except StopIteration:
pass
if __name__ == "__main__":
path = "TB_data_dictionary_2016-04-15.csv"
l1 = []
for i in range(1,10):
start = time.clock()
process_file_1(path)
end = time.clock()
diff = (end - start)
l1.append(diff)
avg = reduce(lambda x, y: x + y, l1) / len(l1)
print('processing time (with generators) {}'.format(avg))
l2 = []
for i in range(1,10):
start = time.clock()
process_file_2(path)
end = time.clock()
diff = (end - start)
l2.append(diff)
avg = reduce(lambda x, y: x + y, l2) / len(l2)
print('processing time (with iterators) {}'.format(avg))
程序的输出:
C:\Python34\python.exe C:/pypen/data_structures/generators/generators1.py
processing time (with generators) 0.028033358176432314
processing time (with iterators) 0.02699498330810426
在上面的程序中,我试图测量使用iterators 和使用generators 打开读取大文件所需的时间。该文件可用here。使用迭代器读取文件的时间远低于使用生成器的时间。
我假设如果我要测量函数 process_file_1 和 process_file_2 使用的内存量,那么生成器将胜过迭代器。有没有办法测量python中每个函数的内存使用情况。
【问题讨论】:
-
在 2 次测试之前执行一次您只需丢弃的读取,以确保操作系统对文件的任何缓存都适用于两次运行。
-
@tdelaney - 我已经稍微更新了程序
标签: python memory profiling generator