CODEWITHSUNDEEP
python-3.x
Sheila
Sheila

Reputation: 9

Find coordinates that are outside a radius

I'm a beginner with Python. I need to get the number of arrows (points) that are outside the radius. I do know what the answer is, but how do I get that output in Python?

This is what I have:

points = [(4, 5), (-0, 2), (4, 7), (1, -3), (3, -2), (4, 5), (3, 2), (5, 7), (-5, 7), (2, 2), (-4, 5), (0, -2),(-4, 7), (-1, 3), (-3, 2), (-4, -5), (-3, 2), (5, 7), (5, 7), (2, 2), (9, 9), (-8, -9)]
center = (0,0)
radius = 9

Upvotes: 0

Views: 75

Answers (1)

Sash Sinha
Sash Sinha

Reputation: 22350

You could use a list comprehension:

import math

points = [(4, 5), (-0, 2), (4, 7), (1, -3), (3, -2), (4, 5), (3, 2), (5, 7),
          (-5, 7), (2, 2), (-4, 5), (0, -2), (-4, 7), (-1, 3), (-3, 2), (-4, -5),
          (-3, 2), (5, 7), (5, 7), (2, 2), (9, 9), (-8, -9)]
center = (0, 0)
radius = 9

points_outside_radius = [
    p 
    for p in points 
    if math.sqrt((p[0] - center[0]) ** 2 + (p[1] - center[1]) ** 2) > radius
]
num_points_outside_radius = len(points_outside_radius)
print(f'There are {num_points_outside_radius} points outside the radius:')
print(points_outside_radius)

Output:

There are 2 points outside the radius:
[(9, 9), (-8, -9)]

Note I used the full euclidian distance formula in case you need to change the center to something other than the origin.

Upvotes: 3

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