迭代步数大于 1 时匹配 js 中的迭代值

Question

当我使用 1 以外的不同迭代步数时如何匹配值？

请看下面的例子。因为 5 是速度，所以我按 5 进行交互。

但是，当我接近 53 时如何停止。如何检测并停止从超过 53 的开始并使其达到 53？

var start=0;

var value_to_reach=53;
var increment_speed=5;
while(true) {


if(start>value_to_reach) 
{
start-=increment_speed
} else { start+=increment_speed  }



if (start==value_to_reach) { 
console.log("reached :" + value_to_reach); //Obviously this will never happen with the increment being +5."
    }
  if (start>54)
    {
    console.log("Let's break this loop for the sake of stopping this infinite loop. But we couldn't achieve what we want. Not reached " + value_to_reach); 
      break;
    }
}

Answer 1

如何检测是否接近53

您可以通过以下方式获得总步数：

var totalRepeation = Math.ceil(value_to_reach / increment_speed);

因此您可以创建一个一个递增的计数器并检查以查看最后一步。

你可以试试这个：

var start = 0;

        var value_to_reach = 53;
        var increment_speed = 5;

        let totalRepeation = Math.ceil(value_to_reach / increment_speed);

        let i = 0;
        while (true) {
            
            if (start > value_to_reach) {
                start -= increment_speed
            } else { start += increment_speed; i++ }

            if (i + 1 >= totalRepeation) {
                console.log("you are close to 53. the start numbre is: ", start)
                break;
            }


            if (start == value_to_reach) {
                console.log("reached :" + value_to_reach); //Obviously this will never happen with the increment being +5."
            }
            if (start > 54) {
                console.log("Let's break this loop for the sake of stopping this infinite loop. But we couldn't achieve what we want. Not reached " + value_to_reach);
                break;
            }
        }

Answer 2

在接近target 时降低步数

在while (start <= reach) 循环中我们可以：

• 检查下一个迭代器是否高于reach
  • 如果是这样，降低迭代器
  • 否则，请保持常规步长
• 增量计数器

let start = 0,
    steps = 5,
    reach = 53,
    debug = 0;

while (start <= reach) {
  
  console.log(`Step: ${steps}, current: ${start}`);
  
  // If next iteration will be above reach
  if ((start + steps) >= reach) {
  
    // Set steps to the diff
    steps = (start + steps) - reach;
  }
  
  // Increment
  start += steps;
}

这将输出：

Step: 5, current: 0
Step: 5, current: 5
Step: 5, current: 10
Step: 5, current: 15
Step: 5, current: 20
Step: 5, current: 25
Step: 5, current: 30
Step: 5, current: 35
Step: 5, current: 40
Step: 5, current: 45
Step: 5, current: 50
Step: 2, current: 52
Step: 1, current: 53

---

如果你想上reach，然后回到target，你可以使用类似：

let start = 0,
    steps = 5,
    reach = 53,
    debug = 0;

do {
  
  console.log(`Step: ${steps}, current: ${start}`);
  
  // If we're above the target
  if (start > reach) {
  
    // Set steps to negative
    steps = -1;
  }
  
  // Increment
  start += steps;
  
  console.log(`Step: ${steps}, current: ${start}`);
} while (start !== reach)