直接貼代碼，摘自問題

import numpy as np

def perp(a):
    b = np.empty_like(a)
    b[0] = -a[1]
    b[1] = a[0]
    return b

# line segment a given by endpoints a1, a2
# line segment b given by endpoints b1, b2
# return


def seg_intersect(a1, a2, b1, b2):
    '''
    查找交點位置兩條直線
    '''
    da = a2 - a1
    db = b2 - b1
    dp = a1 - b1
    dap = perp(da)
    denom = np.dot(dap, db)
    num = np.dot(dap, dp)
    return (num / denom.astype(float)) * db + b1

def main():


    p1 = np.array([2.0, 2.0])
    p2 = np.array([4.0, 3.0])

    p3 = np.array([6.0, 0.0])
    p4 = np.array([6.0, 3.0])

    print(seg_intersect(p1, p2, p3, p4))

main()