CODEWITHSUNDEEP
javascriptnode.js
t33n
t33n

Reputation: 390

Randomize math calculation where we subtract with percentage - node.js/js

Hey :) You can subtract as example 35% from a number with methods like this:

var valueInString = "2383";
var num = parseFloat(valueInString);
var val = num - (num * .35);
console.log(val);

But how is it possible to randomize the .35/0.35 part?

As example if I would try:

var randomREAL = require('randomize');
var randomARR = [30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75]
// randomREAL(randomARR) will generate a random number between 30 - 75 so that I can randomize my percentage value between 30% & 75%

var valueInString = "2383";
var num = parseFloat(valueInString);
var val = num - ( num * 0.randomREAL(randomARR) );
console.log(val);

I can´t use 

0.randomREAL(randomARR)

or

.randomREAL(randomARR)

Also If I would build a string like

var test = randomREAL(randomARR)
0.test

it would not work.

Any ideas how to randomize the percentage value ?

Upvotes: 0

Views: 128

Answers (2)

Gusepo
Gusepo

Reputation: 889

To easily get random numbers between an interval you can use this very simple function from https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random

function getRandomInt(min, max) {
 min = Math.ceil(min);
 max = Math.floor(max);
 return Math.floor(Math.random() * (max - min)) + min; //The maximum is exclusive and the minimum is inclusive
}

Upvotes: 1

Jonas Wilms
Jonas Wilms

Reputation: 138557

+("0."+randomARR[ Math.floor( randomARR.length * Math.random() ) ])

As youve pointed out

Also If I would build a string like

var test = randomREAL(randomARR) 0.test

it would not work.

Because 0. is not a string. You want string concatenation e.g.:

"0."+35

And then you need to parse it back into a number, which can be done with the unary plus operator :

+("0."+35)

Additionally if the number is always two digits, you can also use /100...

Hint: To get a random integer between 30 and 75 is as easy as:

30 + Math.floor( Math.random() * ( 75 - 30 ))

Upvotes: 2

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