对于p5内的循环。js和访问阵列[关闭]

下面是一个解释:

let position = []

// This code only _declares a function called setup. It
// does not run the function.
function setup() {
  let cnv = createCanvas(window.width,window.height);
  cnv.parent('canvas')
  noStroke()
  for(i = 0 ; i < 10 ;i++){
    let x = random(10,20)
    position.push(x)
  }
}

// At this point, you have not added anything to
// position. It's a blank array, because `setup` has
// not been run.
console.log(position[0])

解决方法可能是 console.log 内部 setup 作用

let position = []

function setup() {
  for(i = 0 ; i < 10 ;i++){
    let x = random(10,20)
    position.push(x)
  }

  console.log(position[0])

  let cnv = createCanvas(window.width,window.height);
  cnv.parent('canvas')
  noStroke()
}

function draw(){
  background('#fac81f')
  translate(width/2,height/2)
  ellipse(0,0,width/3)
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.16/p5.min.js"></script>

这样,它只在以下情况下运行 设置 实际上是在运行。