실수를 정수로 바꾸는 방법

참조 : https://www.geeksforgeeks.org/how-to-convert-a-float-number-to-the-whole-number-in-javascript/

 

 

 

How to convert a float number to the whole number in JavaScript?

There are various methods to convert float number to the whole number in JavaScript.

1. Math.floor (floating argument): Round off the number passed as parameter to its nearest integer in Downward direction.
   Syntax:Math.floor(value)

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   <script>   //float value is 4.59;    var x = 4.59;    var z = Math.floor(x);    document.write("Converted value of " + x + " is " + z); </script>

   Output :

   Converted value of 4.59 is 4
2. Math.ceil (floating argument): Return the smallest integer greater than or equal to a given number.
   Syntax:Math.ceil(value)

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   <script>   //float value is 4.59;    var x = 4.59;    var z = Math.ceil(x);    document.write("Converted value of " + x + " is " + z); </script>

   Output :

   Converted value of 4.59 is 5
3. Math.round (floating argument): Round a number to its nearest integer.
   Syntax:Math.round(var);

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   <script>   //float value is 4.59;    var x = 4.59;    var z = Math.round(x);    document.write("Converted value of " + x + " is " + z); </script>

   Output :

   Converted value of 4.59 is 5
4. Math.trunc (floating argument): Return the integer part of a floating-point number by removing the fractional digits.
   Syntax:Math.trunc(value)

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   <script>   //float value is 4.59;    var x = 4.59;    var z = Math.trunc(x);    document.write("Converted value of " + x + " is " + z); </script>

   Output :

   Converted value of 4.59 is 4
5. parseInt (floating argument): Accept the string and convert it into an integer.
   Syntax:parseInt(Value, radix)

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   <script>   //float value is 3.54;    var x = 3.54;    var z = parseInt(x);    document.write("Converted value of " + x + " is " + z); </script>

   Output :

   Converted value of 3.54 is 3
6. double bitwise not (~~) operator: Round a number to towards zero. If the operand is a number and it’s not NaN or Infinity.
   Syntax:~~value

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   <script>   //float value is 4.59;    var x = 4.59;    var z = ~~x;    document.write("Converted value of " + x + " is " + z); </script>

   Output :

   
   Converted value of 4.59 is 4
7. bitwise OR (|) operator: Round a number to towards zero.
   Syntax:var = value | 0;

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   <script>   //float value is 5.67;    var x = 5.67;    var z = x | 0;    document.write("Converted value of " + x + " is " + z); </script>

   Output :

   Converted value of 5.67 is 5
8. Using shift (>>) operator: Round a number to towards zero.
   Syntax:var = value >> 0;

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   <script>   //float value is 5.63;    var x = 5.63;    var z = x >> 0;     //it is same as we are dividing the value by 1.    document.write("Converted value of " + x + " is " + z); </script>

   Output :

   Converted value of 5.63 is 5
9. Using unsigned shift (>>>) operator Round a number to towards zero.
   Syntax:var = value >>> 0;

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   <script>   //float value is 5.68;    var x = 5.68;    //it is same as we are dividing the value by 1.    var z = x >>> 0;     document.write("Converted value of " + x + " is " + z); </script>

   Output :

   Converted value of 5.68 is 5
10. By subtracting the fractional part
    Syntax:var = val - val%1;

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    <script>   //float value is 5.48;    var x = 5.48;    var z = x - x%1;    document.write("Converted value of " + x + " is " + z); </script>

    Output :

    Converted value of 5.48 is 5
11. Using XOR (^) operator
    Syntax:var = value ^ 0;

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    <script>   //float value is 5.49;    var x = 5.49;    var z = x ^ 0;    document.write("Converted value of " + x + " is " + z); </script>

    Output :

    Converted value of 5.49 is 5