我的函数末尾的“返回”似乎不起作用[重复]

Question

我有一个函数，旨在模拟飞盘的轨迹，并基本考虑升力和阻力。飞盘上的力是升力、阻力和重力。它具有预定的发射角度“theta_0”（确定速度角度的角度）和描述飞盘相对于水平“β”的角度的角度。然后，它使用 for 循环来计算每个时间步的位置、加速度和速度。它将这些内容编译到它们自己的单独列表中。如果飞盘到达 gorund (y[-1]<0), it stops the simulation. At the end, I want to return the lists for x and y position, simply titled x and y respectively. However, this does not seem to be working. I have omitted some variables which are defined earlier on in my code to keep the post a bit lighter. Every variable seen in the function should be accounted for.

def trajectory(x_0,y_0,theta_0,v_0, r):

  vx_0 = v_0*(math.cos(theta_0))
  vy_0 = v_0*(math.sin(theta_0))
  A = (math.pi*r**2)

  ax_0 = 0
  ay_0 = -1*g

  t = [0]
  x = [x_0]
  y = [y_0]
  vx = [vx_0]
  vy = [vy_0]
  ax = [ax_0]
  ay = [ay_0]


  for i in range(STEPS):

    theta = math.atan(vy[i]/vx[i])
    alpha = beta_0 - theta

    CD = (0.085 + 3.30*(alpha - (-0.052))**2)
    CL = (0.13 + 3.09*alpha)

    t.append(t[i]+DT)

    x.append(x[i]+vx[i]*DT)
    y.append(y[i]+vy[i]*DT)
    vx.append(vx[i]+ax[i]*DT)
    vy.append(vy[i]+ay[i]*DT)

    drag = float(((-1/2)*RHO*A*CD*alpha*vx[i]**2))
    drag_x = float((drag*math.cos(theta)))
    drag_y = float((drag*math.sin(theta)))

    lift = float(((-1/2)*RHO*A*CL*alpha*vx[i]**2))
    lift_x = float((lift*math.cos(theta)))
    lift_y = float((lift*math.sin(theta)))

    ax.append((1/m)*(-1*lift_x - drag_x))
    ay.append((1/m)*(-m*g + lift_y - drag_y))

    if y[-1]<0:
      del(y[-1])
      del(x[-1])
      del(vx[-1])
      del(vy[-1])
      del(ax[-1])
      del(ay[-1])
      break


  return x,y

trajectory(x_0,y_0,theta_0,v_0,r)
print (x)

上面的代码在尝试打印时返回错误“'x'未定义”。如果我将“x”和“y”的打印语句放在函数内，它们就会打印，但我想绘制结果，所以我需要函数为我返回列表。我知道代码还有其他问题，但我现在并不担心这些问题，我只是想知道是什么导致了这个错误。谢谢！

Answer 1

您没有为函数调用分配任何内容。

尝试：

x,y = trajectory(x_0,y_0,theta_0,v_0,r)
print (x)