如何读取刚刚由python中的函数创建的文件

Posted 2023-03-14

【中文标题】如何读取刚刚由python中的函数创建的文件

【英文标题】：How to read a file that was just created by a function in python

【发布时间】：2019-12-24 08:47:16

【问题描述】：

当我尝试读取刚刚由上面的函数创建的文件时，我得到了空白行。当我在不同的文件中运行相同的代码时，它只运行文件。我看到那个文件已经关闭了。但是当我尝试打开并打印时。我得到空行。

我已将尝试读取的相同代码复制到不同的测试文件并运行该代码。我正在阅读文件并打印行并关闭文件。

def running_symm_list_cmd():
    try:

        path_to_output_file = "symm_list_out.txt"
        myoutput = open(path_to_output_file, 'w')
        symm_list = "sudo symcfg list"
        Popen([symm_list], shell=True, stdout=myoutput, stderr=myoutput, universal_newlines=True)

    except OSError or ValueError as error_str:
        print(error_str)
        os.system(exit(2))
    finally:
        myoutput.close()
        print("checking if file is closed or not ".format(myoutput.closed))


def getting_symm_list():

    try:
        print("INSIDE getting_symm_list TRY  function")
        symm_list = 
        path = "/users/pjinde/scripts/symm_list_out.txt"
        symm_list_file = open(path, 'r')
        print("file mode is m and file name is n".format(m=symm_list_file.mode, n=symm_list_file.name))
        for line in symm_list_file.readlines():
            #print(line)
            symm_ids = re.search(r'(000197\d+)\s+\w+.*', line, re.M | re.I)
            if symm_ids:
                symm_list[symm_ids.group(1)] = None
                #print("Symmetrix id is ".format(symm_ids.group(1)))

        for ids in symm_list.keys():
            print("symmetrix_id are ".format(ids))

    except OSError as err:
        print("unable to get symm list due to error ".format(err))
    finally:
        symm_list_file.close()
    return symm_list

我期待低于输出。这说明我能够创建字典 symm_list。

INSIDE getting_symm_list TRY  function
file mode is r and file name is /users/abcd/efcg/symm_list_out.txt
symmetrix_id are 00019780aaaa
symmetrix_id are 00019780aabc
symmetrix_id are 00019780aadd
symmetrix_id are 00019780aaee
symmetrix_id are 00019780aaff
symmetrix_id are 00019780aaeg
symmetrix_id are 00019790bbbb

非常感谢任何帮助！谢谢。

【问题讨论】：

由于 Popen 运行不对称，您是否尝试过等待 Popen 完成后再关闭文件？ p = Popen(...) p.wait() 只是一个快速的刺，没有 mutchoughtt

我认为你是对的@Svavelsyra。我使用了 subprocess.call 而不是 Popen。我打算使用 Popen，因为我打算通过管道来执行 shell 命令。我改变主意了。

【参考方案1】：

Popen 异步运行，或者我使用 Popen.wait() 直到子进程完成。或者我们可以只使用 subprocess.call

def running_symm_list_cmd():
    try:

        path_to_output_file = "symm_list_out.txt"
        myoutput = open(path_to_output_file, 'w')
        symm_list = "sudo symcfg list"
        p1 = subprocess.call([symm_list], shell=True, stdout=myoutput, stderr=myoutput)

    except OSError or ValueError as error_str:
        print(error_str)
        os.system(exit(2))
    finally:
        myoutput.close()
        print("checking if file is closed or not ".format(myoutput.closed))


def getting_symm_list():

    try:
        symm_list = 
        path = "/users/pjinde/scripts/symm_list_out.txt"
        symm_list_file = open(path, 'r')
        #print("file mode is m and file name is n".format(m=symm_list_file.mode, n=symm_list_file.name))
        for line in symm_list_file.readlines():
            #print(line)
            symm_ids = re.search(r'(000197\d+)\s+\w+.*', line, re.M | re.I)
            if symm_ids:
                symm_list[symm_ids.group(1)] = None
                #print("Symmetrix id is ".format(symm_ids.group(1)))

        for ids in symm_list.keys():
            print("symmetrix_id are ".format(ids))

    except OSError as err:
        print("unable to get symm list due to error ".format(err))
    finally:
        symm_list_file.close()
    return symm_list