如何使用从另一个文件python导入的变量中的值

Question

so I know this has been asked in several forms before, but I cannot relate to any of those, either I have something different or I just don't understand them.

The problem is I have script A and script B, and in script AI calculate and have all the variables I want to use in script B.

Script A has various functions, let's say for now I just want to pass a simple number from a variable in script A to script B , let's call the variable value .

I used from script_A import value .

Now, I have value initialized in script_A with 0 right at the top to say so, but script_A processes value , and gets a result clearly different from 0, but when I debug, I am getting in script_B value == 0 , and not value == calculated_value_that_should_be_there .

I did not know what to do so I tough about scope,so I put it in the return of a function, I tried making variable value a Global variable. Nothing seems to work in the way that I am not passing the calculated 'value' but I am passing to script_B that 0 initialization.

PS last thing I tried and what I saw from this topic is to import script_A as it was said with no namespaces. This has worked. When I write script_A.value it is calculated_value_that_should_be_there. But, I do not know why anything else that I described did not work.

script_A


from definitions import *
variable_1 = 0
variable_2 = 0
variable_3 = 0
variable_4 = 0 

total = 0
respected = 0

time_diff = {}
seconds_all_writes = "write"

class Detect():
    def __init__(self, data_manager, component_name, bus_name_list=None):

 def __Function_A(self):
       """
        global time_diff
        global seconds_all_writes

        process

script_B:
from script_A import respected
from script_A import total


import script_A

        print aln_mon_detector.total
        print aln_mon_detector.respected

I also want a dictionary

table_content.append(script_A.time_diff[file[script_A.seconds_all_writes])

I get

KeyError: 'writes'

Answer 1

this sounds a bit confusing without an example, but, in principle, what you're trying to do should work. Have a look at a minimum example below.

ModuleA - defining the variable

# create the variable
someVariable = 1.

# apply modifications to the variable when called
def someFunc(var):
    return var + 2

# ask for changes
someVariable = someFunc(someVariable)

ModuleB - using the variable

import moduleA

# retrieve variable
var = moduleA.someVariable

print(var) # returns 3

Answer 2

This probably has to do with immutability. Depends on what value is. If value is a list (that is, a mutable object) and you append to it, the change should be visible. However, if you write

from module import x
x = 5

you are not changing the actual value, so other references to x will still show the original object.

Answer 3

If you have script A like this:

# imports

value = 0
...  # some calculations

Re-organize script A as:

# imports

def main():
    value = 0
    ...  # some calculations
    return value

Now you can import script A in script B and run calculations inside script B :

import script_A

value = script_A.main()

That is how you should organize code pieces in Python.