CODEWITHSUNDEEP
pythonfilevariablesimport
Some kid
Some kid

Reputation: 2567

Importing variables from another file?

How can I import variables from one file to another?

example: file1 has the variables x1 and x2 how to pass them to file2?

How can I import all of the variables from one to another?

Upvotes: 241

Views: 673862

Answers (9)

TheOneWithin
TheOneWithin

Reputation: 11

I found that executing a file that declares the variables you want to use loads them in the memory. But one problem about is that it would execute all the commands in the file, so if you wanted just the variables you would need that the file only declare variables. Here's one example:

File1:

a=1
b=3

File2:

with open("File1.py") as file:
    exec(file.read())

c = a+b
print(c)

Output:4

Im new in python so idk if doing this has any other problem, but i thought it was something interesting to share.

Upvotes: 1

Manute
Manute

Reputation: 103

If you need to import of a variable from a dir on the same level or below you can use import_module coming from you cwd of the project:

from importlib import import_module
mod = import_module(
    f"{cwd}.source.myfolder.myfile"
)
var = getattr(mod, "my_variable")

Upvotes: 0

陳仲肯
陳仲肯

Reputation: 325

first.py:

a=5

second.py:

import first
print(first.a)

The result will be 5.

Upvotes: 20

Ravi
Ravi

Reputation: 3217

script1.py

title="Hello world"

script2.py is where we using script1 variable

Method 1:

import script1
print(script1.title)

Method 2:

from script1 import title
print(title)

Upvotes: 14

Lei Z
Lei Z

Reputation: 203

Marc response is correct. Actually, you can print the memory address for the variables print(hex(id(libvar)) and you can see the addresses are different.

# mylib.py
libvar = None
def lib_method():
    global libvar
    print(hex(id(libvar)))

# myapp.py
from mylib import libvar, lib_method
import mylib

lib_method()
print(hex(id(libvar)))
print(hex(id(mylib.libvar)))

Upvotes: 10

Marc Rechté
Marc Rechté

Reputation: 1957

Actually this is not really the same to import a variable with:

from file1 import x1
print(x1)

and

import file1
print(file1.x1)

Altough at import time x1 and file1.x1 have the same value, they are not the same variables. For instance, call a function in file1 that modifies x1 and then try to print the variable from the main file: you will not see the modified value.

Upvotes: 35

Chris Redford
Chris Redford

Reputation: 17778

Best to import x1 and x2 explicitly:

from file1 import x1, x2

This allows you to avoid unnecessary namespace conflicts with variables and functions from file1 while working in file2.

But if you really want, you can import all the variables:

from file1 import *

Upvotes: 83

Ashwini Chaudhary
Ashwini Chaudhary

Reputation: 250901

Import file1 inside file2:

To import all variables from file1 without flooding file2's namespace, use:

import file1

#now use file1.x1, file2.x2, ... to access those variables

To import all variables from file1 to file2's namespace( not recommended):

from file1 import *
#now use x1, x2..

From the docs:

While it is valid to use from module import * at module level it is usually a bad idea. For one, this loses an important property Python otherwise has — you can know where each toplevel name is defined by a simple “search” function in your favourite editor. You also open yourself to trouble in the future, if some module grows additional functions or classes.

Upvotes: 132

ennuikiller
ennuikiller

Reputation: 46965

from file1 import *

will import all objects and methods in file1

Upvotes: 237

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