CODEWITHSUNDEEP
javascriptinputnumbersdecimalrounding
user2829131
user2829131

Reputation:

Round down decimals javascript

I am working on a JS project and i have the following problem:

My input number goes from 0 to 10. (it can be 1, 2, 3.4, 5,9, etc..)

The expected output would be something out of 5 with only one lowered down decimal.

Examples:

9.7 / 10 would give 4.85 / 5 , the output has to be 4.8 (keep only one lowered down digit)

4.9 / 10 would give 2.45 / 5, the output has to be 2.4 (keep only one lowered down digit)

Thanks for your help.

Regards

Upvotes: 3

Views: 1853

Answers (5)

Coisox
Coisox

Reputation: 1104

Does this ugly to you?

Convert to string --> substring --> convert to number

var x = 9.47;
var x2 = (x+'').split(".");
x = parseFloat(x2[0]+"."+x2[1].substr(0,1));

Upvotes: 0

suman das
suman das

Reputation: 367

var x = 4.8555;
x = Math.floor(x * 100) / 100;
alert(x.toFixed(1));

Upvotes: -1

gurvinder372
gurvinder372

Reputation: 68393

try this

var x = 9.7; // input variable
var base = 10; //base like 10 in your case

var outof = 5; //rounded out of

Number(String((x/base)*outof).match(/^\d+(?:\.\d{0,1})?/)) //outputs one rounded off value for last digit;

last line will first compute the value which is 

var value = (x/base)*outof;

then get only first digit after decimal 

value = value.match(/^\d+(?:\.\d{0,1})?/);

convert the final value to a number

value = Number ( value );

Upvotes: 0

James Donnelly
James Donnelly

Reputation: 128791

You can do this with a simple process:

  1. Multiply your number by 10.
  2. Floor it (using Math.floor).
  3. Divide it by 10.
Math.floor(4.85 * 10) / 10; // 4.8
Math.floor(2.45 * 10) / 10; // 2.4
Math.floor(3 * 10) / 10;    // 3

Taking 4.85 as an example:

  1. 4.85 * 10 equates to 48.5.
  2. Math.floor(48.5) equates to 48.
  3. 48 / 10 equates to 4.8.

Upvotes: 3

Hemal
Hemal

Reputation: 3760

You can use .toFixed()

For example

var N=2.45;

alert(N.toFixed(1));

will return 2.4

Upvotes: -1

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