how to append list through other python script?

Question

how to append or create list through other python script?

ex:

1.py

list = [['1', '2'], ['3', '4']]

2.py

import 1
1.list.append('5', '6')

then list becomes

list = [['1', '2'], ['3', '4'], ['5', '6']]

Answer 1

If you meant to 'physically' add the '5' , '6' to the file 1.py , then you need to open 1.py file in the other script and modify the text.

Assume this is your 1.py

.
.
. other lines...

list1 = [1,2,3]

.
.
.
.other lines...

If I assume in your 1.py , there is no other lines that is exactly the same as list1 = [1,2,3] , then you can do this:

with open('1.py', 'rt') as f:
    oldlines = f.readlines()
    
for index,line in enumerate(oldlines):
    if line == "list1 = [1,2,3]":
        # find the line with the text you want to change 
        # You can simply change the text 
        # but what I did here is create the list called list1 
        # then append value to it 
        # then generate the new line and overwrite the orignal line.
        exec(line)
        list1.append(['5','6'])
        oldlines[index] = f'list1 = {list1}'
        break

with open('1.py', 'wt') as f:
    f.write('\n'.join(oldlines))

Your IDE might complain list1 is undefined, but that's OK because the exec(line) is creating list1 for you.

If you meant to modify the list you imported from 1.py while running 2.py , then you need to change the name of 1.py to something like file1.py that doesn't start with number. Because python won't allow module name start with number.

Also you need to change your code slightly:

import file1
file1.list.append(['5', '6'])

Answer 2

Do not call your variables list , dict or the like. That being said, you could use

from other_file import lst
lst.append(['5', '6'])
print(lst)

Which would yield

[['1', '2'], ['3', '4'], ['5', '6']]