查找每个连续线段之间的所有角度

Question

我需要一个 function 来将每个点视为原点，从最接近 (0,0) 的点开始，然后计算从该点到每个其他点的每个线段的角度和长度。 它应该跳过任何会创建之前已经计算过的相同线段的东西

但是，我的 function 并没有考虑到我的第一个点到第二个点的线段。 请帮忙......这是function

import math

def compute_vectors(points):
    vectors = []
    previous = points[0]
    for point in points:
        x = point[0] - previous[0]
        y = point[1] - previous[1]
        angle = math.degrees(math.atan2(y, x))
        if angle < 0:
            angle += 360
        length = math.sqrt(x**2 + y**2)
        vectors.append((angle, length))
        previous = point
    return vectors[1:]
  

points = [[1,1],[2,2],[3,1]] 
compute_vectors(points)

>>> [(45.0, 1.4142135623730951), (315.0, 1.4142135623730951)]

我需要它到 output

>>> [(45.0, 1.4142135623730951),(0.0, 2),(315.0, 1.4142135623730951)]

Answer 1

我认为您想使用嵌套的 for 循环来创建要比较的对。 考虑一个矩阵，其中的值是输入列表的索引列表与其自身的笛卡尔积：

00     01 02 03 04 05
10 11     12 13 14 15
20 21 22     24 24 25
30 31 32 33     34 35
40 41 42 43 44     45
50 51 52 53 54 55

我把对角线分割放在那里是因为你想要的优化（只为尚未考虑的对生成值）可以通过只选择矩阵上半部分的索引对（不包括主对角线）来实现。

这样的事情可能会起作用：

    for idx, pt1 in enumerate(pts):
        for idx2 in range(idx+1, len(pts)):
            pt2 = pts[idx2]
            <do computations with pt1 and pt2>
            .....

像这样使用：

>>> l=[(1, 1), (2, 2), (3, 3), (4, 4)]
>>> for idx, val in enumerate(l):
...   for idx2 in range(idx+1, len(l)):
...     val2 = l[idx2]
...     print(f"point 1 = {val}", f"point2 = {val2}")
... 
point 1 = (1, 1) point2 = (2, 2)
point 1 = (1, 1) point2 = (3, 3)
point 1 = (1, 1) point2 = (4, 4)
point 1 = (2, 2) point2 = (3, 3)
point 1 = (2, 2) point2 = (4, 4)
point 1 = (3, 3) point2 = (4, 4)

Answer 2

import itertools
import math


def compute_angles_and_lengths(points):
  angles_and_lengths = []
  for i in itertools.combinations(points, 2):
    x = i[1][0] - i[0][0] 
    y = i[1][1] - i[0][1]
    lengths = math.sqrt(x**2+y**2)
    angle = math.degrees(math.atan2(y,x))   
    angles_and_lengths.append((angle, lengths))
  return angles_and_lengths


points = [[1,1],[2,2],[3,1]]    
compute_angles_and_lengths(points)

>>> [(45.0, 1.4142135623730951), (0.0, 2.0), (-45.0, 1.4142135623730951)]