p5.js NumberDict mult() Method

The mult() method of p5.NumberDict in p5.js multiplies the given value to the value at the given key and stores the updated value at the same key. A key-value pair is a set of two values that are mapped to each other. These values can be accessed by querying this dictionary using the key portion of the pair. A number dictionary can store multiple key-value pairs that can be accessed using the methods of the dictionary.

Syntax:

mult( Key, Amount )

Parameters: This function has two parameters as shown above and discussed below:

Key: This is a number that denotes the key from where the value would be multiplied.
Amount: This denotes the number to multiply the value by.

The example below illustrates the mult() method in p5.js:

Example:

Javascript

let y = 0; 
  
function setup() { 
  createCanvas(550, 500); 
  textSize(16); 
  
  text("Click on the button to create a new " + 
       "dictionary and multiply the given value", 
       20, 20); 
  
  text("Key:", 20, 260); 
  text("Value:", 160, 260); 
  
  key_input = createInput(); 
  key_input.position(70, 250); 
  key_input.size(40); 
  
  val_input = createInput(); 
  val_input.position(220, 250); 
  val_input.size(40); 
  
  setBtn =  
    createButton("Create random dictionary"); 
  setBtn.position(30, 40); 
  setBtn.mouseClicked(createNewDict); 
  
  multBtn =  
    createButton("Multiply given value to key"); 
  multBtn.position(30, 300); 
  multBtn.mouseClicked(mulVal); 
} 
  
function createNewDict() { 
  clear(); 
  
  // Create an object with random values 
  let obj = {}; 
  for (let i = 0; i < 6; i++) { 
    let rk = ceil(Math.random() * 100); 
    let rn = floor(Math.random() * 100); 
    obj[rk] = rn; 
  
    text("Key: " + rk + " : Value: " + 
         rn, 40, 120 + 20 * i); 
  } 
  
  // Create a number dict using the above values 
  numDict = createNumberDict(obj); 
  
  text("New Dictionary created with values", 20, 80); 
  
  text("Click on the button to create a new " + 
       "dictionary and multiply the given value", 
       20, 20); 
  
  text("Key:", 20, 260); 
  text("Value:", 160, 260); 
} 
  
function mulVal() { 
    
  // Get the key and value to be updated 
  let keyToChange = int(key_input.value()); 
  let valToMul = int(val_input.value()); 
  
  // Get the previous value in the dictionary 
  let prevVal = numDict.get(keyToChange); 
  
  // If the key exists in the dictionary 
  if (prevVal) { 
    numDict.mult(keyToChange, valToMul); 
  
    // Get the updated value 
    let updatedVal = numDict.get(keyToChange); 
    
    text("The value at key: " + keyToChange + 
         " was: " + prevVal, 20, 360 + y * 40); 
    text("The updated value at key: " + 
         keyToChange + " is: " + updatedVal, 
         20, 380 + y * 40); 
  } 
  else { 
    text("Please enter a proper key", 20, 380 + y * 40); 
  } 
  
  y = y + 1; 
  text("Click on the button to create a new " + 
       "dictionary and multiply the given value", 
       20, 20); 
} 

Output:

Online editor: https://editor.p5js.org/
Environment Setup: https://www.w3wiki.net/p5-js-soundfile-object-installation-and-methods/
Reference: https://p5js.org/reference/#/p5.NumberDict/mult

Javascript

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