The problem of obtaining Random numbers by js

for example, if you get a random number of 0 to 10, you can think of the following two kinds of 

Math.ceil(Math.random()*10);
Math.floor(Math.random()*(10+1));

but see that someone says to use Math.ceil (Math.random () * 10); the chance of taking 0 is very small.
when you use Math.floor (Math.random ()) * (10: 1));), you can get a balanced random integer from 0 to 10.
is this really the case? Is it possible to use floor instead of ceil to get random numbers later?

Javascript html5
Feb.28,2021

ceil is rounded up, and Math.ceil (Math.random () * 10) is 0 only when 0 is taken, so the probability is very small.
floor is rounded down, Math.ceil (Math.random () *) (10: 1)), equals that you take between 0 and 11, and the number you get is rounded down. Relatively speaking, the integer probability of getting 0-10 is about

.

if it is an integer of [0code 10], the standard method is Math.floor (Math.random () * (103.1))
if it is an integer of [0heroin 10), the standard method is Math.floor (Math.random () * 10)
there is a problem no matter how you handle it with ceil.

if it is an integer of (0 code 10], the standard method is Math.ceil (Math.random () * 10) , then there will be problems with floor.

this is a mathematical problem. First of all, you have to understand that Math.ceil is rounded up, that is, if a decimal such as 0.0000000000000000000000001 is rounded up, it will also be 1 ; then there is the question of value range, $Math.random ()\ in [0,1) $$, $Math.ceil (Math.random ())\ in [0,1] $) after rounding up, at this time, $$Math.ceil (Math.random ()) = 0,1) is a necessary and sufficient condition for $Math.random. Suppose Math.random () is an ideal random number generator (accurate to infinity after the decimal point), then $$P (Math.random () = 0) = 0 percent, and if Math.random () is accurate to n place after the binary decimal point, then $$P (Math.random () = 0) = 1 / 2 ^ n $. See for yourself how small the probability is.

upstairs has explained the difference very well. There is another way to try ~ (0 + Math.random () * 10)

.

Previous: How to get the statistics of google meals?

Next: How can Vue.js add content to the template?

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
© 2021 CodesHelper
Advertising Contact us About us
Menu