This question already has answers here:
Making a random number that's a multiple of 10
(7 answers)
Closed 5 years ago.
Guys, I wanted to know how can I generate a number, for example between 5 and 100 but only 5 by 5, for example, it would generate 5, 10, 15, 20 up to 100, but not any other number.
I've tried using Math.floor(Math.random() * (100 - 5 + 1)) + 5but i can't seem to figure out how it can generate 5 by 5 numbers and I really need it right now.
I'm still an amateur so please no flame.
function randomIntStep(min,max,step) {
return min + Math.floor(Math.random() * max / step) * step;
}
Related
This question already has answers here:
Generating random whole numbers in JavaScript in a specific range
(40 answers)
How does Math.floor(Math.random() * (Max - Min + 1) + Min) work in JavaScript? (Theory)
(3 answers)
Closed 8 months ago.
I came across the following command:
Math.floor(Math.random() * 10 + 1);
I understand that Math.floor() will convert to the lowest integer, but what does Math.random() * 10 + 1 do?
Math.random returns a floating point number x such that:
Multiplying 10 to x yields a floating point number in the range:
And then adding 1 to 10x yields a floating point number in the range:
And finally flooring 10x + 1 yields an integer in the range:
Therefore, Math.floor(Math.random() * 10 + 1) yields an integer that lies in the range [1, 10].
Math.random generates a random number between 0 and 1. So for example it can be .124 or .42242. When you multiply this random number against something, you are basically making it so that the new result is no less than 0, but no more than the number you are multiplying it against.
So in your example, you are multiplying it against 10, which means you will get a random number between 0 and 10 with decimals; technically this range is 'more than 0, but less than 10'. The +1 just increases the total range so that it is between 1 and 11, or 'more than 1, but less than 11.
When you apply Math.floor() to this, you are rounding all of these results down. So in the case without the '+1', your finite range is actually 0-9, and with the +1 it is 1-10
This question already has answers here:
Generating random whole numbers in JavaScript in a specific range
(40 answers)
Closed 1 year ago.
I got this javascript code that returns a random integer number between 1 and 10.
I got a problem making it return a random number between -7 and -12.
You gotta bail me out of this one, please...
const a = Math.floor(Math.random() * (10 - 1)) + 1;
console.log(`Random value between 1 and 10 is ${a}`);
The difference between -7 and -12 = 5.
First, change your code to give a random number between 0-4 (or 1-5) instead of 1-10.
After that, subtract 12 from the outcome.
This question already has answers here:
Generating random whole numbers in JavaScript in a specific range
(39 answers)
Closed 6 years ago.
I wan't to generate a random number and use it as a class name for an element.
Math.random();
This will generate a random number '0.7220265011042561'
Since this will be used as a class within the class attribute of an element, the decimal will surely cause problems and most likely isn't valid.
How can I generate a random whole number?
Math.round( Math.random()*10000000 )
This will generate a random whole number between 1 and 100.
Math.floor((Math.random() * 100) + 1);
Change the 100 part to redefine your range.
Add however many significant digits you want with the 100000 part:
Math.floor(Math.random() * 100000);
If you want them the same length, for smaller numbers (e.g., 5), here's a left-padded version:
var sigFig = // (put the number of significant digits you want here)
var number = Math.floor(Math.random() * Math.pow(10, sigFig));
var numStr = String(number);
while (numStr.length < sigFig) {
numStr = '0' + numStr;
}
// do stuff with numStr
Edit: Moved the significant figure to a variable.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Generating random whole numbers in JavaScript in a specific range
How can I get one-digit random numbers (1, 2, 3, ..., not 0.1, 0.2, ... or 1.0, 5.0, ...) using Math.random() or some other way in JavaScript?
Math.random() returns a float between 0 and 1, so just multiply it by 10 and turn it into an integer:
Math.floor(Math.random() * 10)
Or something a little shorter:
~~(Math.random() * 10)
Disclaimer:
JavaScript's math.rand() is not cryptographically secure, meaning that this should not be used for password, PIN-code and/or gambling related random number generation. If this is your use case, please use the web crypto API instead! (W3C).
If the digit 0 is not included (1-9):
function randInt() {
return Math.floor((Math.random()*9) + 1);
}
If the digit 0 is included (0-9):
function randIntWithZero() {
return Math.floor((Math.random()*10));
}
var randomnumber=Math.floor(Math.random()*10)
where 10 dictates that the random number will fall between 0-9.
Math.floor((Math.random()*10));
And there goes your random integer between 0 and 10!
Use this:
Math.floor((Math.random()*9)+1);
This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
Generating random numbers in Javascript
I have the following code var randomnumber=Math.floor(Math.random()*101); that generates a random number for me between 1 and 100. What I would like to do is generate a random number between -100 and 100. I am not sure what to do exactly. Any help would be appreciated.
First, generate a random number between 1 - 200 then subtract 100:
var randomNumber = Math.floor(Math.random() * 201) - 100;
var randomnumber=Math.floor(Math.random()*200)-100;