# Random probability (Customizing random function)

**URL:** <https://discourse.processing.org/t/random-probability-customizing-random-function/18571>\
**Category:** Coding Questions\
**Created:** [March 10, 2020, 4:52pm UTC](https://discourse.processing.org/t/random-probability-customizing-random-function/18571 "2020-03-10T16:52:36Z")\
**Posts on this page:** 1\
**Showing post:** 8

<div class="post-metadata">

**Author:** ![noel](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/noel/32/213_2.png) [@noel](https://discourse.processing.org/u/noel)\
**Post date:** [March 16, 2020, 10:44am UTC](https://discourse.processing.org/t/random-probability-customizing-random-function/18571/8 "2020-03-16T10:44:21Z")

</div>

The idea of customizing the random function consists in creating an array of for instance 1000 integers, each with a value from 0 to, for instance, 500. Such an array can be created by drawing a line in a window from left to right with the height y giving the value of index x.

When these indexes are randomly accessed, the chance of picking a lower or higher value is determined by the shape of the line shown in the picture. Customized random tables are sometimes used in games. Another usage you can find on [this topic.](https://discourse.processing.org/t/help-to-create-image-from-interaction-with-website/18315/7)  
The code will generate a one-line string of the customized random table in the console that can be copied/pasted into the other sketch.

```auto
float x, y, old_x, old_y, targetX, targetY;
float easing = 0.11; // increase for more details
boolean down, begin = true;
String str = "";
int i, j=0;

void setup() {
  size(1000, 500);
  smooth();
  erase();
}

void draw() {
  if (down) {
    if (begin) {
      old_x = 0; 
      old_y = mouseY;
      x = mouseX;
      y = mouseY;
      begin = false;
    }
    targetX = mouseX;
    targetY = mouseY;
    x += (targetX - x) * easing;
    y += (targetY - y) * easing;   
    line(old_x, old_y, x, y);
    old_x = x;
    old_y = y;
  }
}

void mousePressed() {
  if (mouseX > width-200 && mouseX < width-120 && mouseY < 30) send();
  if (mouseX > width-100 && mouseY < 30) erase();
} 

void mouseDragged() {
  down = true;
} 

void mouseReleased() {
  down = false;
} 

void send() {
  // searching for black pixels is needed because when drawing
  // some pixels may have been missed
  down = false;
  for ( i = 0; i <= width; i++) {
    for (j = 0; j <= height; j++) {
      color c = get(i, j);
      if (c == color(0)) {
        str += str(height-j)+',';  
        break;
      }
    }
  }
  println ("int[]num={"+str+"};");
  exit();
}

void erase() {
  begin = true;
  stroke(0);
  strokeWeight(2);
  background(255);
  fill(230);
  rect(width-200, 5, 80, 30);
  rect(width-100, 5, 80, 30);
  fill(0);
  text("Save", width-190, 25);
  text("Clear", width-90, 25);
}

```

![table](https://canada1.discourse-cdn.com/flex036/uploads/processingfoundation1/original/2X/0/0508ebbf46585d820b7bc883ce76d9d81d16e6e5.gif)

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