我如何将十进制值转换为一位数字

Question

Here is my question

I want to convert 0.21 to 0.29 to 2

then 0.31 to 0.39 to 3 till 0.99 to 9

and so one

I went to this function but it didn't help

function myFunction() {
    var num = 0.89;
    var n = num.toFixed(1);
    document.getElementById("demo").innerHTML = n +1;
}

Answer 1

Try using the following:

function myFunction(num) {
  document.getElementById("demo").innerHTML = Math.floor(num*10);
}

Answer 2

Easiest way to achieve what you want is:

 var num = 0.89; var n = Math.floor(num * 10) % 10; document.getElementById("demo").innerHTML = n; 

 <div id="demo"></div> 

Without using any math functions. Because you want X of 0.XYZ every time.

Answer 3

You could use factor for flooring.

 function format(v) { var d = Math.floor(Math.log10(v)); return Math.floor(v / Math.pow(10, d)); } console.log([0.2, 0.89, 0.023, 5432].map(format)); 

Answer 4

var integer_value = Math.floor(num*10); // gives required integer value

Explanation:

If your number is 0.ABC, you want A, you can do this by multiplying 0.ABC by 10, which makes it A.BC and then using Math.floor on A.BC to get A.

Cases:

When 0.ABC:

• 0.012 --> Math.floor(0.12) ---> 0
• 0.213 --> Math.floor(2.13) ---> 2
• 0.290 --> Math.floor(2.90) ---> 2
• 0.988 --> Math.floor(9.88) ---> 9

toFixed(0)

toFixed(sig_digits) will give you a string representation of the number till a certain number of significant digits. Using that with sig_digits 0, will round it off, so cases like 8.99 will get rounded off to 9, instead of 8.