Question

在我进入我的问题之前，该计划的一些背景知识：

我正在尝试创建一个模拟抢劫的程序。强盗，警卫和门都有硬编码值。

随着while循环的每次迭代，强盗移近门以逃脱。此外，每次循环迭代，守卫都会越来越靠近强盗。这两个操作都由 computeChanges 函数处理。

如果强盗在守卫到达他之前（0,0）到达门口，那么强盗就会逃跑，并打印卫兵的最后位置。

如果守卫在进入门前抓住强盗，则会打印强盗和守卫的最后位置。

我在执行时遇到的问题是强盗和守卫的值在传递到 computeChanges 函数后没有改变。这会导致无限循环。

我错过了什么？重新分配X和Y位置应该在 computeChanges 函数的最后两行发生。

感谢任何和所有帮助。

代码：

from numpy import arctan, sin, cos
from math import pi, copysign, sqrt

# Used to prevent objects from overshooting one another
def normalizeSpeed(speed1, speed2, maxSpeed):
    if speed1 > speed2:
        larger = speed1
    elif speed2 > speed1:
        larger = speed2
    speed1 = speed1 / larger * maxSpeed
    speed2 = speed2 / larger * maxSpeed

# Used to compute the change in position for given object
def computeChanges(movingX, movingY, speed, targetX, targetY):
    bigTriangleWidth = movingX - targetX
    bigTriangleHeight = movingY - targetY
    bigTriangleRatio = bigTriangleWidth / bigTriangleHeight
    bigTriangleAngle = arctan(bigTriangleRatio)

    ratioX = sin(bigTriangleAngle)
    changeX = ratioX * speed
    ratioY = cos(bigTriangleAngle)
    changeY = ratioY * speed

    movingX += copysign(changeX, bigTriangleWidth * -1)
    movingY += copysign(changeY, bigTriangleHeight * -1)


# Used to calculate the absolute distance between two objects to be compared to the closeEnough variable
def absDistance(object1X, object1Y, object2X, object2Y):
    diffX = object2X - object1X
    diffY = object2Y - object1Y
    d = sqrt(diffX ** 2 + diffY ** 2)
    return abs(d)

#------------------------------------------------------------------------#
#------------------------------------------------------------------------#

robberX = -10.0
robberY = 100.0
robberSpeed = 11

guardX = -5.0
guardY = 140.0
guardSpeed = 13

normalizeSpeed(robberSpeed, guardSpeed, 0.1)

doorX = 0.0
doorY = 0.0

closeEnough = 0.2

while ((absDistance(robberX, robberY, guardX, guardY) > closeEnough) and (absDistance(robberX, robberY, doorX, doorY) > closeEnough)):
    computeChanges(robberX, robberY, robberSpeed, doorX, doorY)
    print("Robber position: ({0}, {1})".format(robberX, robberY))
    computeChanges(guardX, guardY, guardSpeed, robberX, robberY)
    print("Guard position: ({0}, {1})".format(guardX, guardY))

if (absDistance(robberX, robberY, doorX, doorY) <= closeEnough):
    print("The robber escapes!\nguardX = {0}\nguardY = {1}".format(guardX, guardY))
elif (absDistance(robberX, robberY, guardX, guardY) <= closeEnough):
    print("The guard catches the robber!\nrobberX = {0}\nrobberY = {1}\nguardX = {2}\nguardY = {3}".format(robberX, robberY, guardX, guardY))

Answer 1

你的问题在于python处理变量范围的方式。是的，在computeChanges的最后一行，您正在更改movingX和movingY。但是，您只是在该函数体的范围内更改那一个调用的变量。一旦函数完成，那些局部变量就会被丢弃。

你应该退出这两个变量并更新while循环中的强盗和守卫位置。

def computeChanges(movingX, movingY, speed, targetX, targetY):
    ...
    return movingX, movingY

...

while ((absDistance(robberX, robberY, guardX, guardY) > closeEnough) and (absDistance(robberX, robberY, doorX, doorY) > closeEnough)):
    robberX, robberY = computeChanges(robberX, robberY, robberSpeed, doorX, doorY)
    print("Robber position: ({0}, {1})".format(robberX, robberY))
    gaurdX, gaurdY = computeChanges(guardX, guardY, guardSpeed, robberX, robberY)
    print("Guard position: ({0}, {1})".format(guardX, guardY))

银行抢劫模拟器

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