将变量从一个python脚本导入另一个

Question

I have script1.py which calls script2.py (subprocess.call([sys.executable, "script2.py"]) . But script2.py needs variable x that is known in script1.py . I tried a very simple import x from script1 , but it seems not to work.

Is that the right approach to use? For example:

#script1.py
import subprocess, sys
##subprocess.call([sys.executable, 'C:\\...\\Desktop\\script2.py'], shell=True)
##os.system("C:\\...\\Desktop\\script2.py")
subprocess.Popen("C:\\...\\Desktop\\script2.py", shell=True)
print "BLAH"
x = BO

#script2.py
from script1 import x
print "HELLO"
print x

All 3 cases of calling script2 (subprocess.call, os.system, subprocess.Popen ) do not work. I get "BLAH" but not "HELLO".

Answer 1

The correct syntax is:

from script1 import x

So, literally, "from script1.py import the "x" object."

Answer 2

Try this:

from script1 import x

I just ran the following pieces of code and it worked

script1:

c = 10

script2:

from script1 import c
print c

The second script printed the integer 10 as you should expect.

Oct 17 Edit: As it stands the code will either not produce the "Hello" as indicated or will go into an infinite loop. A couple of issues:

As it stands, BO is undefined. When you execute script1, the subprocess of script2 is opened. When script2 calls script1, it will print out blah but fail on x=BO as BO is undefined.

So, if you fix that by specifying BO with say a string, it will go into an infinite loop (each script calling the other one and printing x, Hello and Blah).

One potential way to fix it is to pass x through a function call. So, script2 could take x as a function parameter and do whatever you need to do with it.

Answer 3

Your code is looping because the subprocess.Popen call is in the module initialization code, so it will be called by script2 when importing script1 (creating a new script2 process that also imports script1 ...)

The recommended way of having a python file usable as both a script and a module is to use the __name__ variable

#script1.py

x = BO

if __name__ == "__main__":
    import subprocess, sys
    subprocess.Popen("C:\\...\\Desktop\\script2.py", shell=True)
    print "BLAH"

But also consider this only works for constants . If x can change at runtime you will need an actual interprocess communication method.

Answer 4

script1.py:

x = 2
from script2 import *

script2.py:

from script1 import x
print x

Answer 5

Script 0:

#!/usr/bin/env python
from script1 import x

print x

Script 1:

#!/usr/bin/env python
x = "Hello world"

Output:

Hello world

So yeah it does work, no need for sub processes.

Answer 6

我认为你必须通过在script2.py中为其模块名称（即script1.x）添加前缀来引用该变量

Answer 7

The method being used is more complex than is necessary. After fixing BO (I assumed it is meant as a string literal, so I quoted it), and assuming the scripts are co-located, you can call script2 and get the result you are after.

See the following:

#script1.py
print "BLAH"
x = "BO"

#script2.py
from script1 import x
print "HELLO"
print x

$ python script2.py 
BLAH
HELLO
BO