python 将函数变量传递给另一个函数

Question

我试图将变量从一个函数传递到我在单独文件中的主引擎函数。我查阅了其他答案并浏览了一些，但我似乎无法理解它..

load_file.py

def get_connection():
    cursor = connection.cursor()
    cursor.execute(
        "SELECT ID, Type, Server, Port, User, Password, isActive, FileExtension, FileContains, FileLocation, "
    "ScheduleMinutes, IntervalTime from DataConnection WHERE isActive=True")

    data_connection = cursor.fetchall()


def download_files(data_connection):
    for data_connection_detail in data_connection:
        connection_type = data_connection_detail[1]

        if connection_type == 'IMAP':
             ez_email.read_email_imap(data_connection_detail)

        elif connection_type == 'POP3':
             ez_email.read_email_pop3(data_connection_detail)

        elif connection_type == 'FTP':
             ez_ftp.easy_ftp(data_connection_detail)

main.py

from load_file import download_files
from load_file import get_connection

def run_engine():
    while True:
        get_connection()
        download_files()


if __name__ == "__main__":
    run_engine()

当我将 'data_connection' 传递给 'download_files' 函数时，它说我的 main.py 引擎中有一个未填充的参数。

如果这个问题已经得到解答，我很抱歉，但我无法理解它。

Answer 1

行

def download_files(data_connection):

表示传递一个参数

我想你可能想要

def run_engine(): 而真实的： conn = get_connection() download_files(conn)

get_connection 函数对我来说看起来很奇怪，好像它不是返回连接而是返回 fetchall 的结果。

Answer 2

您的 download_files() 函数有一个必需的参数 (data_connection)。当您在 run_engine 中调用它时，您没有传递参数。

您需要从 get_connection 捕获返回的变量并将其传递给 download_files，如下所示：

data_con = get_connection()  # place the returned variable from get_connection into a variable called data_con
download_files(data_con)     # pass that data_con variable to the download_files function

但是 get_connection 的返回值实际上并不是您当前代码中的连接 - 您需要确保 returning/passing 是正确的变量。

Answer 3

load_file.py

def get_connection():
        cursor = connection.cursor()
        cursor.execute(
            "SELECT ID, Type, Server, Port, User, Password, isActive, FileExtension, FileContains, FileLocation, "
        "ScheduleMinutes, IntervalTime from DataConnection WHERE isActive=True")
    
        return cursor.fetchall()

def download_files(data_connection):

        for data_connection_detail in data_connection:
            # type email will be IMAP, POP3, or FTP
            connection_type = data_connection_detail[1]

            # create data_source object
            if connection_type == 'IMAP':
                ez_email.read_email_imap(data_connection_detail)

            elif connection_type == 'POP3':
                ez_email.read_email_pop3(data_connection_detail)

            elif connection_type == 'FTP':
                ez_ftp.easy_ftp(data_connection_detail)

main.py

from load_file import get_connection
from load_file import download_files

def run_engine():
    while True:
        data = get_connection()
        download_files(data)



if __name__ == "__main__":
    run_engine()

这种情况下的解决方案是 return 来自第一个函数的对象，并将其用作第二个函数的参数。

python 将函数变量传递给另一个函数

python passing function variables to another function

python

function

parameter-passing