Question

我陷入困境，因为我在范围（x）循环中没有迭代。我的计划的目的是模拟在岛上彼此相互作用的狐狸和兔子，并在每天后打印出每个动物的种群。我知道方程是正确的，我遇到的问题是我的循环只会在大范围内运行一次。

我的代码：

def run_simulation():
    print()
    RABBIT_BIRTH_RATE = 0.01
    FOX_BIRTH_RATE = 0.005
    INTERACT = 0.00001
    SUCCESS = 0.01
    x = 0
    y = 1
    FOXES = eval(input("Enter the initial number of foxes: "))
    print()
    RABBITS = eval(input("Enter the initial number of rabbit: "))
    print()
    DAYS = eval(input("Enter the number of days to run the simulation: "))
    print()
    print("Day\t","Rabbits\t","Foxes\t")
    print(0,"\t",RABBITS,"\t","\t",FOXES,"\t")
    for i in range(DAYS):
        RABBITS_START = round((RABBIT_BIRTH_RATE * RABBITS) - (INTERACT * RABBITS * FOXES))
        FOXES_START = round((INTERACT * SUCCESS * RABBITS * FOXES) - (FOX_BIRTH_RATE * FOXES))
        y = y + x
        print (y,"\t",(RABBITS_START+RABBITS),"\t","\t",(FOXES_START+FOXES),"\t")
run_simulation()

如果使用500 Foxes，10000 Rabbits和1200天的示例运行，我的输出将如下所示

Day  Rabbits     Foxes  
0    10000       500    
1    10050       498

第二条输出线重复剩余的1199次。任何帮助将不胜感激我无法弄清楚我做错了什么。

Answer 1

您在开头设置了RABBITS和RABBIT_BIRTH_RATE。然后，在每次循环迭代中，将RABBITS_START设置为涉及这两个数字的某个公式。您永远不会更改RABBITS或RABBIT_BIRTH_RATE或FOXES或任何内容的值，因此每次执行循环时，您只需使用相同的数字再次计算相同的内容。您需要在每次迭代时更新变量的值 - 也就是说，为RABBITS，FOXES等设置新值。

Answer 2

对我而言，最大的问题就是你所谓的“兔子/狐狸的变化”。 RABBITS_START听起来像RABBITS的初始计数，但事实并非如此。这就是为什么我将它重命名为RABBITS_DELTA，因为它实际上是在计算每天兔子的变化。

我想我明白了。至少，这个行为现在更像是模拟：

def run_simulation():
  RABBIT_BIRTH_RATE = 0.01
  FOX_BIRTH_RATE = 0.005
  INTERACT = 0.00001
  SUCCESS = 0.01
  x = 0
  y = 1

  FOXES = eval(str(input("Enter the initial number of foxes: ")))
  RABBITS = eval(str(input("Enter the initial number of rabbits: ")))

  DAYS = eval(str(input("Enter the number of days to run the simulation: ")))

  print("Day\t","Rabbits\t","Foxes\t")
  print(0,"\t",RABBITS,"\t","\t",FOXES,"\t")

  count = 0
  while count < DAYS:
    RABBITS_DELTA = round((RABBIT_BIRTH_RATE * RABBITS) \
                          - (INTERACT * RABBITS * FOXES))
    FOXES_DELTA = round((INTERACT * SUCCESS * RABBITS * FOXES) \
                        - (FOX_BIRTH_RATE * FOXES))
    y = y + x

    RABBITS += RABBITS_DELTA
    FOXES += FOXES_DELTA
    print (y,"\t",(RABBITS),"\t","\t",(FOXES),"\t")

    count += 1


run_simulation()

Answer 3

我会试图解释你的意思：

for i in range(1, DAYS + 1):
    rabbit_delta = ... # RABBITS_START
    fox_delta = ... # FOXES_START
    RABBITS += rabbit_delta
    FOXES += fox_delta
    print(i, "\t", RABBITS, "\t\t", FOXES, "\t")

根据他人的回答

编辑。（野生刺伤不太狂野。）

请参阅BrenBarn的答案，以解释散文。

Answer 4

我想这就是你的意思

def run_simulation():
    print()
    RABBIT_BIRTH_RATE = 0.01
    FOX_BIRTH_RATE = 0.005
    INTERACT = 0.00001
    SUCCESS = 0.01
    x = 0
    y = 1
    FOXES = int(input("Enter the initial number of foxes: "))
    print()
    RABBITS = int(input("Enter the initial number of rabbit: "))
    print()
    DAYS = int(input("Enter the number of days to run the simulation: "))
    print()
    print("Day\t","Rabbits\t","Foxes\t")
    print(0,"\t",RABBITS,"\t","\t",FOXES,"\t")
    for i in range(1, DAYS + 1):
        RABBITS += round((RABBIT_BIRTH_RATE * RABBITS) - (INTERACT * RABBITS * FOXES))
        FOXES += round((INTERACT * SUCCESS * RABBITS * FOXES) - (FOX_BIRTH_RATE * FOXES))
        y = y + x
        print (i,"\t",(RABBITS),"\t","\t",(FOXES),"\t")

run_simulation()

我得到的输出是

Day Rabbits Foxes
0 10000 500
1 10050 498
2 10100 496
3 10151 494
4 10202 492

天= 4

循环不迭代

4 个答案: