此代码与 python 线程模块是否安全？

Question

Is my.txt file always hold 100 lines? Does this code guarantee that there is no data loss?

import threading
import os

class Worker(threading.Thread):
    def __init__(self, name):
        super().__init__()
        self.name = name            

    def run(self):
        os.system("echo {} >> my.txt".format(self.name))

for i in range(100):
    name = "thread {}".format(i)
    t = Worker(name)                
    t.start()                       

Answer 1

You are using >> for the shell redirection. This opens the file in append mode, and the OS guarantees that all data is written at the end of the file in that mode, so no data will get lost. However, when writing a lot of data, lines from different sources may be intermingled in unpredictable ways.

Launching a new shell for each line you write isn't really required. You can open files in append mode directly from Python using with open("my.txt", "a") as f: ... .