How to select radom items in a for loop in jQuery-CodePudding

how to select random items inside a jQuery loop. I have a loop with 30 items where I'm adding some random numbers, now I don't want to add random numbers to all items at once, I would like to add random numbers to random items in the loop.

A good example would be, let's say I want my loop to add 5 to several random items of a loop as shown below

for( var i = 0; i < 30; i    ){
                 if( i 'is in range of radom'  ){
                    i   5;
                 } else {
                    i   0;
                 }
            }

It's like selecting a bunch of items inside a loop, next time selecting another bunch and so on. I can select like 10 random items in a loop to add 5 to, next loop another random 10 items are selected and so on and so forth.

CodePudding user response：

Assuming you mean your 30 items is an array of 30 numbers.

Assuming you want to add a value (in your example, 5) to n random items (in your example, 10 items)

const items = [/* 30 things here */];
for (let i = 0; i < 10; i  ) {
   items[Math.random() * items.length]  = 5;
}

This could possibly add 5 to the same item 10 times, if Math.random() returns similar values.

CodePudding user response：

Consider the following.

function getRandomInt(max) {
  return Math.floor(Math.random() * max);
}

var random = [];

for (var i = 0; i < 5; i  ) {
  random.push(getRandomInt(30));
}

var results = [];

for (var i = 0; i < 30; i  ) {
  if (random.indexOf(i) >= 0) {
    results[i] = i   5;
  } else {
    results[i] = i;
  }
}

console.log(random, results);

Assuming random is an array of "random" entries, you can populate a new array with 30 entries, in order, with salted results.

Results:

You can use .indexOf():

The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present.

If you have an Array of Numbers for example, you can check if a Number is in that array this way.