javascript从数组中删除

Question

你好，我的代码运行了，但是当我与星星碰撞时，它会擦除​​屏幕上的所有内容，但是我需要做的就是从屏幕上移除星星，但将其他所有内容都保留在原处，因为我计划为每个记分板做一个记分板后来收集的星星。

stars=[];
 stars.push({
   x: 420,
   y:  580,
width: 5,
height: 5

 });


function update() {

var score = 0; // score starts at 0

// check keys
if (keys[38] || keys[32]) {
    // up arrow or space
    if (!player.jumping && player.grounded) {
        player.jumping = true;
        player.grounded = false;
        player.velY = -player.speed * 2;
    }
}
if (keys[39]) {
    // right arrow
    if (player.velX < player.speed) {
        player.velX++;
    }
}
if (keys[37]) {
    // left arrow
    if (player.velX > -player.speed) {
        player.velX--;
    }
}

player.velX *= friction;
player.velY += gravity;

ctx.clearRect(0, 0, width, height);
ctx.fillStyle = "black";
ctx.beginPath();

player.grounded = false;
for (var i = 0; i < boxes.length; i++) {
    ctx.rect(boxes[i].x, boxes[i].y, boxes[i].width, boxes[i].height);

    var dir = colCheck(player, boxes[i]);



    if (dir === "left" || dir === "right") {
        player.velX = 0;
        player.jumping = false;
    } else if (dir === "bottom") {
        player.grounded = true;
        player.jumping = false;
    } else if (dir === "top") {
        player.velY *= -1;
    }

  }
for (var i = 0; i < stars.length; i++) {
    ctx.rect(stars[i].x, stars[i].y, stars[i].width, stars[i].height);

    var dir = colCheck(player, stars[i]);

    if(dir != null)
    {
delete stars[0];
//stars.splice(a);
//var resultObject = search.splice(0,1);
 }


     if (dir === "left" || dir === "right") {
        player.velX = 0;
        player.jumping = false;
    } else if (dir === "bottom") {
        player.grounded = true;
        player.jumping = false;
    } else if (dir === "top") {
        player.velY *= -1;
    }

}


  if(player.grounded){
     player.velY = 0;
}

player.x += player.velX;
player.y += player.velY;

ctx.fill();
ctx.fillStyle = "blue";
ctx.fillRect(player.x, player.y, player.width, player.height);

  requestAnimationFrame(update);
   }

Answer 1

更换

delete stars[0];

同

stars.splice(i,1);
i--;

我没有发现其他任何错误。

Answer 2

您需要向后遍历数组。 这是因为删除元素时数组的长度将更改（并且元素的索引将减少一），因此您当前的代码将跳过某些元素。 另外，正如deme72所说，您将要使用.splice(index, count)从数组中删除项目。 请参阅下面的更新代码：

for (var i = stars.length - 1; i >= 0; i--) {
    // Other code
    stars.splice(i, 1);
}