How to get the variable from one instance of an object, into another object in the same file?

Question

I'm trying to get the maximum and minimum value from another object in the same file. But it keeps returning " object has no attribute 'max_value' ". Can someone tell me how to get the variables for every instance of the object? Here is the full code:

from math import *
from graphics import *


def compute_min_and_max(expression):

    #Various constants
    print("Evaluating ", expression)
    min_value = 1e200
    max_value = -1e200


    #Gets maximum and minimum for x between 0 and 10
    for i in range(0, 1001):

        try:
            x = i/100.0
            y = eval(expression)
            min_value = min(y, min_value)
            max_value = max(y, max_value)

        except Exception:
            print("For ", x, " the expression is invalid")
            pass


    print("Your min and max numbers are *drum roll*...")
    return(min_value, max_value)


def compute_min_and_max_for_file(filename):

    global_min = 1e200
    global_max = -1e200
    opened_function_file = open(filename, 'r')

    #Gets global max and min
    for line in opened_function_file:
        compute_min_and_max(line)
        global_max = max(compute_min_and_max(line).max_value, global_max)
        global_min = min(compute_min_and_max(line).min_value, global_min)


    #Closes file, and returns the values
    opened_function_file.close()
    return (global_min, global_max)

Answer 1

You have no objects. You have only got functions, and the max_value name is a local variable.

You do return a tuple of both min_value and max_value, but you ignore that return. Use tuple assignment to capture both:

for line in opened_function_file:
    min_value, max_value = compute_min_and_max(line)
    global_max = max(max_value, global_max)
    global_min = min(min_value, global_min)