我正在创造一个捕食者-猎物的模拟

Question

这是我现在的代码

#this is the input for population and predators
popOne=float(input("Enter the predator population : "))  20

popTwo=float(input("Enter the prey population :")) 1000

#period is the amount of iterations, in my case 10
period=float(input("Enter the number of periods: ")) 10

#This is the values for the given periods
A=float(input("Enter the value .1: ")) .1
B=float(input("Enter the value .01 : ")) .01
C=float(input("Enter the value .01 : ")) .01
D=float(input("Enter the value .00002: ")) .00002

#Formluas from my book for prey population, and predator population

prey=(popTwo*(1+A-(B*popOne)))

pred=(popOne*(1-C+(D*popTwo)))

i=0
for i in range(10):
    print(prey)
    print(pred)
    i = i+1 

最后一部分是我犯错误的地方。我无法让代码打印出第一次迭代，然后继续进行第二次、第三次，依此类推。在

另外，如何使输出看起来像：

^{pr2}$

等等。在

Answer 1

您需要将填充更新代码放入循环中。我还建议对初始总体也使用pred和prey变量。下面是一些代码：

pred = float(input("Enter the predator population : ")) # use pred and prey here
prey = float(input("Enter the prey population :"))

periods = int(input("Enter the number of periods: "))

A=float(input("Enter the value .1: ")) # these should have better prompts
B=float(input("Enter the value .01 : "))
C=float(input("Enter the value .01 : "))
D=float(input("Enter the value .00002: "))

for i in range(periods):
   # update both pred and prey at once (so no temp vars are needed)
   # also, lots of unneeded parentheses were removed
   prey, pred = prey*(1 + A - B*pred), pred*(1 - C + D*prey)

   print("After period {} there are {:.0f} predators, and {:.0f} prey"
         .format(i, pred, prey))