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How to read a value from another python file after file write?

I am new to Stackoverflow so I will try to ask the question as detailed as possible. I am facing an issue where I call a function to write a value to a python file, and another function to return this written value. However, the function that supposed to return this written value does not return the most updated value after the write function.
I have done multiple researches and tried multiple methods from other questions posted in Stackoverflow but it still didn't work for me.
Here is what I currently have:
In test.py
import random
import string
from test_value import *
def write():
letters = string.ascii_letters
value_to_be_passed = ''.join(random.choice(letters) for i in range(10))
f = open("test_value.py", "w")
f.write('value="' + value_to_be_passed + '"')
f.close()
def read():
print(value)
write()
read()
In test_value.py
value="MutmHDlVQj"
If you run this file, it will generate a new string and store this new string into test_value.py. But when the function read() runs, it does not print out the newly generated string. It seem as though when I run this program, python will immediately store the value in test_value.py in it's memory and does not return the new value when called.
I have tried fsync, flush, with open but it still doesn't work. It won't be ideal to read the file as a plaintext as I might be storing multiple variables in test_value.py so that my program can call the value of the respective variables.
You can run the code in your ide, upon the first run it will print MutmHDlVQj in your terminal even though the goal is supposed to print the newly generated string.
Does anyone know how this could be solved? Thank you in advance.
Workaround Solution
Thanks to tripleee that gave me the idea of this cheap solution. However, I am sure there are better methods that can be done to solve this issue. May the experts give your opinions on this!
Instead of importing at compile time, I ran the importing when I really needed it.
def read():
from test_value import *
print(value)

The import happens when your script is compiled, before it runs and writes anything to the new file. If you want to import something during runtime, you can do that with importlib; but this seems fundamentally like an XY problem. If your task is to serialize some data, use pickle or simply save the data in a standard format like JSON.

from import method you can't pass a variable so simply for a return value, you must specify in test_value.py a return function.
here's the functioning code:
import random
import string
from test_value import value
def write():
letters = string.ascii_letters
value_to_be_passed = ''.join(random.choice(letters) for I in range(10))
f = open("test_value.py", "w")
f.write('value="' + value_to_be_passed + '"')
f.close()
def read():
returned_value = value()
print(returned_value)
write()
read()
in test_value.py:
def value():
value="SbjvLSYfNs"
return value
written like this I have a functioning code that prints the value returned from another python file like you asked.
hope it helps in the future, but remember that if you want to return a value, you must specify the return function

How do I call a function in vs code using python?

I'll want to know how to call a function in vs code. I read the answer to similar questions, but they don't work:
def userInput(n):
return n*n
userInput(5)
And appends nothing
def Input(n):
return n*n
And in the terminal:
from file import *
from: can't read /var/mail/file
Can somebody help me?

You are doing everything correctly in the first picture. In order to call a function in python on vs code you first have to define the function, which you did by typing def userInput(n):. If you want to see the result of your function, you should not use return, you should use print instead. Return is a keyword- so when your computer reaches the return keyword it attempts to send that value from one point in your code to another. If you want to see the result of your code, typing print (n) would work better.
Your code should look like this:
def userInput(n):
print (n * n)
userInput(5)
The code would print the result 25

Your terminal is your general way to access your operating system, so you have to tell it that you want it to interpret your Python code first.
If you want to run the file you're typing in, you have to first know the location of that file. When you type ls in your terminal, does the name of your Python file show up? If not, hover over the tab in VSCode (it's close to the top of the editor) and see what path appears. Then in your terminal type cd (short for "change directory") and then the path that you saw, minus the <your filename here>.py bit. Type ls again, and you should see your Python file. Now you can type python <your filename here>.py to run it (provided you have Python installed).
You could also run the IDLE by just typing python in your terminal. This will allow you to write your code line-by-line and immediately evaluate it, but it's easier to write in VSCode and then run it with the method I described before.

Neither atom or visual code shows dataset output

I have downloaded a Kaggle Netflix csv (here). Then I tried to open it using the following code on both atom and visual studio:
import pandas as pd
datapath='~/Downloads/netflix_titles_nov_2019.csv'
netflixdata=pd.read_csv(datapath)
netflixdata.describe()
It runs without error but does not output anything. However, when I do it on the terminal it shows the .csv information.
Am I missing something? Like an extension, etc..

When running commands in terminal, things operate differently. If you are running your code in an IDE of sorts, you need to tell your code to display the output. If you just want to visually see it, this can be done as easy as just printing the output with print(netflixdata.describe())

tl;dr
If you are expecting output from a script, you should surround it with print.
Explanation
In Python, the way an object is displayed is governed by its __repr__ function (think "representation"). Here's an example:
class MyUncoolClass:
pass
class MyCoolClass:
def __repr__(self):
return "Check out this repr"
>>> MyUncoolClass()
<__main__.MyUncoolClass object at 0x1063c0048>
>>> MyCoolClass()
Check out this repr
When you call netflixdata.describe(), you get a data frame back:
>>> type(netflixdata.describe())
<class 'pandas.core.frame.DataFrame'>
What you are actually viewing when you call .describe() in the shell is the output of the dataframe's __repr__ function, which is a string. This string will be shown when you print it, or when it's displayed in the console. However, when you run a python script, unless you (or something else) explicitly calls print on some object, it will not be printed.

Trouble importing files in Python

I'm just finding out now that when importing a module, it seems to run through ALL the code, instead of just the one function that I want it to go through. I've been trying to find a way around this, but can't seem to get it. Here is what is happening.
#mainfile.py
from elsewhere import something_else
number = 0
def main():
print('What do you want to do? 1 - something else')
donow = input()
if donow == '1':
something_else()
while 1:
main()
#elsewhere.py
print('I dont know why this prints')
def something_else():
from mainfile import number
print('the variable number is',number)
Now, although this code KIND OF works the way I want it to, the first time when I initiate it, it will go to the main menu twice. For example: I start the program, press one, then it asks me what I want to do again. If I press one again, then it will print "the variable number is 0".
Once I get this working, I would like to be importing a lot of variables back and forth. The only issue is,if I add more import statements to "elsewhere.py" I think it will just initiate the program more and more. If I put "from mainfile import number" on line 1 of "elsewhere.py", I think this raises an error. Are there any workarounds to this? Can I make a different file? What if I made a class to store variables, if that is possible? I'm very new to programming, I would appreciate it if answers are easy to read for beginners. Thank you for the help.

As Jan notes, that's what import does. When you run import, it runs all of the code in the module. You might think: no it doesn't! What about the code inside something_else? That doesn't get run! Right, when the def statement is executed it creates a new function, but it doesn't run it. Basically, it saves the code for later.
The solution is that pretty much all interesting code should be in a function. There are a few cases which make sense to put at the top-level, but if in doubt, put it inside a function. In your particular case, you shouldn't be printing at the top level, if you need to print for some reason, put that into a function and call it when you need it. If you care when something happens, put it in a function.
On a second node, don't import your primary script in other scripts. I.e. if your mainfile.py directly, don't import that in other files. You can but it produces confusing results, and its really best to pretend that it doesn't work.
Don't try to import variables back and forth. Down that path lies only misery. You should only be importing things that don't change. Functions, classes, etc. In any other case, you'll have hard time making it do what you want.
If you want to move variables between places, you have other options:
Pass function arguments
Return values from a function
Use classes
I'll leave it is an exercise to the reader to learn how to do those things.

import executes imported code
import simply takes the Python source file and executes it. This is why it prints, because that instruction is in the code and with import all the instructions get exectued.
To prevent execution of part of imported package/module, you shall use the famous:
if __name__ == "__main__":
print("I do not print with `import`")
Note, that this behaviour is not new in Python 3, it works the same way in Python 2.x too.

An interpretation error for a python multithreading and multiprocessing

I want to compare multithreading and multiprocessing python program. But, I got interpretation error:
File "./parallelPython.py", line 23
time fornorm(g,range(100))
^
SyntaxError: invalid syntax
The code is as follows:
#!/usr/bin/python -tt
import numpy as np
import math
def f(x):
print x
y = [1]*10000000
[math.exp(i) for i in y]
def g(x):
print x
y = np.ones(10000000)
np.exp(y)
from handythread import foreach
from processing import Pool
from timings import f,g
def fornorm(f,l):
for i in l:
f(i)
time fornorm(g,range(100))
time fornorm(f,range(10))
time foreach(g,range(100),threads=2)
time foreach(f,range(10),threads=2)
p = Pool(2)
time p.map(g,range(100))
time p.map(f,range(100))
I do not why fornorm() has a problem, it has been defined !!!
thanks

It doesn't say fornorm hasn't been defined, it says you have a syntax error on the line where you're calling fornorm. Syntax errors mean Python can't even understand your code: it's as if I say to you "flrk ask web ski ur lkjq", and then ask you to do what I said. An error about fornorm not being defined would happen much later. As it is, Python can't even tell whether you're asking it to call a function, let alone whether you're calling one that is already defined or not.
It looks like your error is this:
time fornorm(g,range(100))
That looks like you're trying to use the shell command time. Shell commands are not Python, and Python doesn't understand it.
However, your code as pasted into SO also has indentation errors, which should have triggered a syntax error earlier than that line, so I suspect what we can see here is not exactly what you were running.

It looks like an Indentation error here :
def fornorm(f,l):
for i in l:
f(i)
After your def python is expecting an indented block.
By the way, time something is an IPython "magic" function and it won't work in a script file. You should import timeit module and use that instead.

Where are you getting "time" from? That's not a valid python statement. It's not like shell scripting.
If you want to time stuff, use the timeit library:
http://docs.python.org/library/timeit.html