Adding a data with Probability K.

[haku87]

Sorry, I has this problem with probability adding.

Let say every time i called a function AddX(), it return a true or false. With a probability of 0.2,

Every 5 time that I called this function Add(X), 1 time it will return me true and 4 time false. How to do that?

[oni-kun]

<?php
function addX() {
  $rand = rand(1,5);
  if ($rand == 1) { return true; } else { return false; }
}
?>

Is that what you meant? This will generate a random number, giving it a probability of 0.2(20%) to be true, 80% chance to be false.

[Alex]

<?php
function addX() {
  $rand = rand(1,5);
  if ($rand == 1) { return true; } else { return false; }
}
?>

Is that what you meant? This will generate a random number, giving it a probability of 0.2(20%) to be true, 80% chance to be false.

You could shorten that, just to make it look a little nicer:

 

<?php
function addX() {
  return (rand(1, 5) == 1) ? true : false;
}
?>

[oni-kun]

You could shorten that, just to make it look a little nicer:

 

This is a shorter example, but he is learning and it's best to understand how the method works before working on shorthand logic for this.. It will not be as easy to understand for a beginner.

[roopurt18]

Let say every time i called a function AddX(), it return a true or false. With a probability of 0.2,

Every 5 time that I called this function Add(X), 1 time it will return me true and 4 time false. How to do that?

 

Well which is it?  Do you want it to return true 20% of the time and false 80% of the time?  Or out of 5 calls do you want it to return true at least once without knowing which of the 5 calls it will be?  Because they are not the same thing.