# How would you do this?

Discussion in 'Python' started by eli m, Feb 28, 2013.

1. ### eli mGuest

How would you find the slope, y intercept, and slope-intercept form equation for a line in python?

eli m, Feb 28, 2013

2. ### Dave AngelGuest

On 02/27/2013 10:32 PM, eli m wrote:
> How would you find the slope, y intercept, and slope-intercept form equation for a line in python?
>

First, I'd form a more complete description of the problem. Specify
what the overall constraints are (eg. Python version, OS portability,
where input is to be gotten, and what the input values are to mean, how
results are to be represented)

Then, I'd write a series of tests, especially showing both parameters
that will work, and parameters that should give exceptions.

Then, I'd break the problem description into steps in a pseudo code
form. For example, maybe get the input parameters (which are they, and
in what order) from the command line. Validate the inputs, and make sure
an answer is possible. Then apply this formula, and print the result.
Apply that formula and print the result. Apply the third formula and
print the result. Exit the program.

Next, I'd translate that pseudo code into actual Python statements, and
type it into a text editor.

Then run those tests, and for each that fails, either revise the test or
the code, depending on which is wrong.

If you run into trouble on one of these steps, show us your work, and
somebody will undoubtedly be able to help there.

--
DaveA

Dave Angel, Feb 28, 2013

3. ### Steven D'ApranoGuest

On Wed, 27 Feb 2013 19:32:40 -0800, eli m wrote:

> How would you find the slope, y intercept, and slope-intercept form
> equation for a line in python?

I would post a message to a Python forum and ask a vague question that

But if I actually wanted an answer, I'd give the post a sensible subject
line, and make an effort to explain my actual problem. For instance:

"I have an equation written as a string, like '2y - 6x + 3 = 0'. How
should I parse the string to extract the slope and intercept from the
equation, and re-write it in the form 'y = mx+c'?"

Or:

"I have a bitmap image of a line graph. How do I detect the lines in the
image, decide which ones are the axes, and determine the slope and
intercept of the plotted line?"

Or:

"How do I get the slope and intercept of a Line object from the
the-internet.com?"

Or:

"Can somebody google the formula for slope and intercept of a line for
me, 'cos I can't be bothered."

The answers you get will depend on which question you actually ask.

--
Steven

Steven D'Aprano, Feb 28, 2013
4. ### Michael TorrieGuest

On 02/27/2013 08:32 PM, eli m wrote:
> How would you find the slope, y intercept, and slope-intercept form
> equation for a line in python?

Well, how do you do it by hand? Once you have the basic formula or
algorithm down, just translate it into python. Math is math. We can
answer specific questions of course. Like, how would I represent the
equation in python? Well put each term in a variable. For example,
3x^2-2x+4 = 0, you would store the 3, 2, and 4 in variables. Then run