Call Python function w/ values from a locally set up module-CodePudding

I have a module named my_math set up with basic functions inside, such as:

def triangle(base, height):
    return base*height/2

When I import my_math in the terminal (python3) and call the function w/ parameters like this it gives me the answer:

>>> import my_math
>>> my_math.triangle(2, 8)
8.0

However, if I place the values for base and height inside or outside in the function in the my_math module and try to call the function using those values, I receive an error:

# my_math.py
base = 3
height = 4

def triangle(base, height):
    # base = 3
    # height = 4
    return base*height/2

# trying it at the interpreter prompt
>>> my_math.triangle(base, height)

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'base' is not defined. Did you mean: 'False'?

How can I make the code use the values defined in the module instead?

CodePudding user response：

One option is to import all variables and methods from the module, like so:

from my_math import *

triangle(base,height)
# returns 6

Alternatively, you could statically reference the variables directly from the module:

import my_math

my_math.triangle(my_math.base, my_math.height)
# returns 6

CodePudding user response：

I'm not sure why you'd want to do this, and it's usually better to just put in the parameters each time.

You could set default parameters for your functions like this:

def myFunction(value1 = 10, value2 = 10):
   pass

this will set the values to 10 if nothing is passed in for them: more on this

But as far as I'm aware, this really doesn't work and it's better practice to pass in your arguments each time.

CodePudding user response：

In Python, variables are defined only locally unless otherwise specified. This means that in the scope of your function, those variables are not defined. Declaring them as globals should fix your issue:

global base
base = 3
global height
height = 4

def triangle():
    global base
    global height
    # base = 3
    # height = 4
    return base*height/2