python3：如何将 append 列表转换为外部 python 文件中的空列表？

Question

There is a list-

#main_file.py
f = ['foo','bar']

that I want to append to an empty list in an external python file.
The external file already has an empty list g

#external_file.py
g = []

So far I have tried this in the main file-

#main_file.py
h = open("external_file.py", "a")
g.append(f)
h.close()

But it didn't work

Answer 1

You can do

import re

with open("external_file.py", "r+") as h:
    stmt = h.read()
    exec(stmt)
    val_name = stmt[:stmt.find("=")].strip()
    eval(val_name).extend(f)
    h.seek(0)
    h.write(re.sub("\[.*\]", str(eval(val_name)), stmt))

Because you are reading for a file then the statement "g = []" is text so you need to exec() it the it will be converted to g = [] .
After there is a need to extend the f list in to the g and to remove the original "g = []" with the new extended list and write it back to the file.

Answer 2

You can try by importing the first external_file.py and then append the list f from the main_file.py

#main_file.py

import external_file as externalFile
f = ['foo','bar']
externalFile.g.append(f)
#print(externalFile.g)