Revisiting-Concepts-Notations-Software-Art/2.Ghost-Writing.md

Ghost Writing: Text, Arrays, Randomness

Sketch: 2.0 Array + Index

// Array + Index!

var NAMES = ["David", "Karin", "Sigrid", "Nanna", "Laura", "Maaike"];
var INDEX = 0;
    
function setup() {
  createCanvas(400, 400);
}

function draw() {
  background(220);
}

function keyTyped() {
  if(key == 'x') {
    print("Hi " + NAMES[0] + "!");
  }
}

// Reference: https://p5js.org/reference/

🤔 What are indices?

 ["David", "Karin", "Sigrid", "Nanna", "Laura", "Maaikke"]  <--- Array (var NAMES)
     |        |         |        |         |        |
     0        1         2        3         4        5		<--- indices (var INDEX)

📚 Exercice

1. Modify sketch 2.0 so that:

• When key 'k' is pressed then "Hi Karin!" is printed on the console
• When key 's' is pressed then "Hi Sigrid!" is printed on the console
• When key 'n' is pressed then "Hi Nanna!" is printed on the console
• When key 'm' is pressed then "Hi Maaike!" is printed on the console

2. Modify sketch 2.0 so that:

• Every time key 'x' is pressed then print the name of the following person in the array ("Hi David!", "Hi Karin!", "Hi Sigrid!", and so forth)

🤔 Who/what is "undefined"?

Sketch: 2.1 Array + Index + Loop

// Array + Index + Loop!

var NAMES = ["David", "Karin", "Sigrid", "Nanna", "Laura", "Maaike"];
var ACTIVITIES = ["piano", "tennis", "chess", "records"];
var INDEX = 0;
    
function setup() {
  createCanvas(400, 400);
}

function draw() {
  background(220);
}

function keyTyped() {
  if(key == 'x') {
    for(let i = 0; i < 4; i++) {
      print(NAMES[INDEX] + " likes to play " + ACTIVITIES[i]);  
    }
  }
}

// Reference: https://p5js.org/reference/

🤔 How do for-loops work?

for(let i = 0; i < X; i++) {
  // do_somethings();
}

where the 3 statements

-> "let i = 0" is the declaration and initialisation of the control variable (i)
-> "i < X" is the continuation condition (i.e. if the condition is true, then executed the statement in the loop > do_something();, exit the loop when it is false)
-> "i++" is the incremental/update statement that is executed at the end of the loop (i.e. after the statement in the loop as been executed)