python - 为子进程写入文件输入

Question

我需要在循环中调用一个例程，该例程将文本文件作为输入。因为我不想一直打开和关闭文本文件，所以我在循环中保持打开状态。例如:

with open("test.txt",'r+') as w_file:

    w_file.write(str(0.8) + "\n" + str(0.2))
    subprocess.call(["cat","test.txt"]) #Here I want to call my routine

但文件仍处于旧状态。为什么？处理这个问题的最佳方法是什么？

Answer 1

写入后需要关闭文件。尝试:

with open("test.txt",'r+') as w_file:
    w_file.write(str(0.8) + "\n" + str(0.2))

subprocess.call(["cat","test.txt"]) #Here I want to call my routine

或者不关闭，刷新文件

with open("test.txt",'r+') as w_file:
    w_file.write(str(0.8) + "\n" + str(0.2))
    w_file.flush()
    subprocess.call(["cat","test.txt"]) #Here I want to call my routine