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arrays

class overview

  • Homework Solution
  • Adding & Removing
  • Array.filter()
  • Array.map()
  • Views Exercise
  • Homework Overview

ADDING & REMOVING

  • Add items to the end of an array with Array.push(value)
  • Remove an item by using it's index and Array.splice(index, howMany)
 
 var arr = [];
 arr.push("trot");
 arr.push("prance");
 arr.push("jog");
//['trot', 'prance', 'jog']
//remove prance
 arr.splice(1, 1);
//['trot', 'jog']

ARRAY.FILTER()

  • Creates a new array filtered by a custom criteria
  • First argument is a function to test each element. Returning true will include that element in that result.
//gets even numbers 
[1,2,3,4,5].filter(function(value, index, arr) {
     return value % 2 == 0;
 });

//[2,4]


ARRAY.MAP()

  • Creates a new array by calling the provided function on each value.
  • First argument is the function to be called.
 
//add 5 to each number
[1,2,3,4,5].map(function(curVal, index, arr) {
     return curVal + 5;
});
//[6,7,8,9,10]



views exercise

  • Make a page with multiple views
  • Navigation should be via JavaScript

cool js thing for the day

Open API's

AJS Lecture 11: More Arrays

By Ryan Lewis

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AJS Lecture 11: More Arrays

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