I have a collection of basic cartesian coordinates and I'd like to manipulate them with Python. For example, I have the following box (with coordinates show as the corners):
0,4---4,4
0,0---4,0
I'd like to be able to find a row that starts with (0,2) and goes to (4,2). Do I need to break up each coordinate into separate X and Y values and then use basic math, or is there a way to process coordinates as an (x,y) pair? For example, I'd like to say:
New_Row_Start_Coordinate = (0,2) + (0,0)
New_Row_End_Coordinate = New_Row_Start_Coordinate + (0,4)
Sounds like you're looking for a Point class. Here's a simple one:
class Point:
def __init__(self, x, y):
self.x, self.y = x, y
def __str__(self):
return "{}, {}".format(self.x, self.y)
def __neg__(self):
return Point(-self.x, -self.y)
def __add__(self, point):
return Point(self.x+point.x, self.y+point.y)
def __sub__(self, point):
return self + -point
You can then do things like this:
>>> p1 = Point(1,1)
>>> p2 = Point(3,4)
>>> print p1 + p2
4, 5
You can add as many other operations as you need. For a list of all of the methods you can implement, see the Python docs .
depending on what you want to do with the coordinates, you can also misuse the complex numbers:
import cmath
New_Row_Start_Coordinate = (0+2j) + (0+0j)
New_Row_End_Coordinate = New_Row_Start_Coordinate + (4+0j)
print New_Row_End_Coordinate.real
print New_Row_End_Coordinate.imag
Python doesn't natively support elementwise operations on lists; you could do it via list comprehensions or map
but that's a little clunky for this use case. If you're doing a lot of this kind of thing, I'd suggest looking at NumPy .
For a = (0,2)
and b = (0,0)
a + b
will yield (0, 2, 0, 0)
, which is probably not what you want. I suggest to use numpy
's add
function: http://docs.scipy.org/doc/numpy/reference/generated/numpy.add.html
Parameters : x1, x2 : array_like
Returns: The sum of x1 and x2, element-wise. (...)
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