Question

我正在构建一个进化模拟应用程序，如果某个有机体的健康状况超过75％，它就会繁殖，然后将健康状况减去一半。为此，我创建了该对象所属类的新实例，然后将该对象推入存储其他生物的数组。由于我不知道的原因，这使p5.js崩溃。

我试图减少有机体的数量（3），并根据班级的情况来写。

var organisms = []; // array where organisms instances go

function reproduce(){
  for (let i = 0; i < organisms.length; i++){
     if(organisms[i].life > 0.75){
        // create a genetically similar size
        let size = organisms[i].size + (random() > 0.5 ? 1 : -1 * random() * 2);   
        // declare instance
        let org = new Organism(width, height, size)
        organisms.push(org);
        // prevent infinite reproduction
        organisms[i].life -= 0.5;
        }
    }
}

我希望这只会创建新的类实例，但是会使p5.js崩溃。

Answer 1

遍历数组并创建新的生物，然后在循环之后将新创建的生物的数组添加到原始数组中。

这是一个可运行的代码段，它创建了一个最小的示例。问题中对方法random的调用已替换为对Math.random()的调用，并且声明了width和height以消除对p5.js的需求。

    var organisms = []; // array where organisms instances go
    var width = 100;
	var height = 100;
	
	function Organism(w, h, s){
	this.width = w;
	this.height = h;
	this.size = s;
	this.life = .76;
	}
	organisms.push(new Organism(1,1,1));
    console.log("Organisms length before reproduce: " + organisms.length);
	reproduce();
    console.log("Oganisms length after reproduce:  "+organisms.length);

    function reproduce(){
      var organismsToAdd = [];
      for (let i = 0; i < organisms.length; i++){
         if(organisms[i].life > 0.75){
            // create a genetically similar size
            let size = organisms[i].size + (Math.random() > 0.5 ? 1 : -1 * Math.random() * 2);   
            // declare instance
            let org = new Organism(width, height, size)
            organismsToAdd.push(org);
            // prevent infinite reproduction
            organisms[i].life -= 0.5;
            }
        }
      //organisms = organisms.concat(organismsToAdd);
      // or
	  organisms.push.apply(organisms, organismsToAdd)
    }

这是带有p5.js的可运行代码段

      var organisms = []; // array where organisms instances go

function setup(){
  createCanvas(100,100);
  	organisms.push(new Organism(1,1,1));
  noLoop();
  }
  
  function draw(){
   console.log("Organisms length before reproduce: " + organisms.length);
  	reproduce();
    console.log("Organisms length after reproduce: " + organisms.length);
  }
    function reproduce(){
      var organismsToAdd = [];
      for (let i = 0; i < organisms.length; i++){
         if(organisms[i].life > 0.75){
            // create a genetically similar size
            let size = organisms[i].size + (random() > 0.5 ? 1 : -1 * random() * 2);   
            // declare instance
            let org = new Organism(width, height, size)
            organismsToAdd.push(org);
            // prevent infinite reproduction
            organisms[i].life -= 0.5;
            }
        }
  //    organisms = organisms.concat(organismsToAdd);
	  organisms.push.apply(organisms, organismsToAdd)
    }
	  
	function Organism(w, h, s){
	  this.width = w;
	  this.height = h;
	  this.size = s;
	  this.life = .76;
	}

<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.8.0/p5.min.js"></script>

Answer 2

您创建的循环条件可能永远不会结束。

for (let i = 0; i < organisms.length; i++){

在第一次迭代中，假设生物具有5个元素。如果满足下一行的if条件，则将另一个元素添加到organisms数组中。下一次迭代将更改organisms中的下一个元素，但是由于数组每次都增加一个，因此您将永远无法到达数组的末尾！

为什么此函数（将对象推送到数组）会崩溃p5.js？

2 个答案: