这篇文章主要介绍了Python3并发写文件原理解析,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下
这篇文章主要介绍了Python3并发写文件原理解析,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下
使用python2在进行并发写的时候，发现文件会乱掉，就是某一行中间会插入其他行的内容。
但是在使用python3进行并发写的时候，无论是多进程，还是多线程，都没有出现这个问题，难道是python3的特性吗？
import time import os import multiprocessing from multiprocessing.dummy import Pool as ThreadPool def write(val, file): w = open(file, "a") for i in range(100): w.write("%s\n" % val) time.sleep(0.001) def thread_write(file): res, pools = [], ThreadPool(10) for i in range(10): val = str(i) * 1000 res.append(pools.apply_async(func=write, args=(val, file, ))) while res: for ret in res: if ret.ready(): res.remove(ret) time.sleep(0.01) def mutil_write(file): pools = multiprocessing.Pool(processes=10) res = [] for i in range(100): res.append(pools.apply_async(thread_write, args=(file, ))) while res: for ret in res: if ret.ready(): res.remove(ret) time.sleep(0.01) if __name__ == '__main__': file = "./write_test" mutil_write(file) with open(file) as fb: lines = 0 line_len = [] for line in fb: lines += 1 line = line.strip() line_len.app<strong style="color:transparent">来源gaodai#ma#com搞@@代~&码*网</strong>end(len(line)) if len(line) != 1000: raise(Exception("error line: %s, len: %d" % (line, len(line)))) print("lines:%d, max len:%d, min:%d, avg:%.2f" % (lines, max(line_len), min(line_len), sum(line_len)/len(line_len))) os.remove(file)
上面代码，多进程并发写结束后，校验每一行的长度是否是设置好的长度。用python3反复运行，均通过测试没有异常。
$ python3 --version Python 3.7.4 $ python3 t.py lines:10000, max len:1000, min:1000, avg:1000.00
如果用python2，则会出现异常：
$ python2 --version Python 2.7.15 $ python2 t.py Traceback (most recent call last): File "t.py", line 49, in raise(Exception("error line: %s, len: %d" % (line, len(line)))) Exception: error line: 333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333330000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000, len: 1092
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转载请注明原文链接：Python3并发写文件与Python对比
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