[Javascript] Ressources pour manipuler les tableaux

Doc généraliste

La doc officielle de developer.mozilla.org – en français, très bien faite avec des exemples manipulables en live à la jsFiddle!
JavaScript Arrays Tutorial sur le site de Dynamic Web Coding (EN)

Code snippets

Comment ajouter des éléments à un tableau?

var ar = ['one', 'two', 'three']; ar[3] = 'four'; // add new element to ar

1
2

var ar = ['one', 'two', 'three'];
ar[3] = 'four'; // add new element to ar

Comment ajouter des URLs contenus dans un menu (UL>LI) dans un tableau?

<ul class="menu sidebar-navigation vertical accordion-menu">
    <li class="is-accordion-submenu-parent">
        <a href="http://www.local/site_disabled/fr/home-static.html" class="link" onclick="" title="">Accueil</a>
    </li>
    <li class="is-accordion-submenu-parent">
        <a href="http://www.local/site_disabled/fr/flightlist-a-static.html" class="link" onclick="" title="">Arrivées du jour</a>
    </li>
    <li class="is-accordion-submenu-parent">
        <a href="http://www.local/site_disabled/fr/flightlist-d-static.html" class="link" onclick="" title="">Départs du jour</a>
    </li>
    <li class="is-accordion-submenu-parent">
        <a href="http://www.local/site_disabled/fr/companylist-static.html" class="link" onclick="" title="">Compagnies aériennes</a>
    </li>
</ul>

<a href="http://www.local/site_disabled/fr/home-static.html" class="link" onclick="" title="">Accueil</a>

</li>

<a href="http://www.local/site_disabled/fr/flightlist-a-static.html" class="link" onclick="" title="">Arrivées du jour</a>

</li>

<a href="http://www.local/site_disabled/fr/flightlist-d-static.html" class="link" onclick="" title="">Départs du jour</a>

</li>

<a href="http://www.local/site_disabled/fr/companylist-static.html" class="link" onclick="" title="">Compagnies aériennes</a>

</li>

</ul>

var staticNavURLs = [];
$mobileMenu.find('a').each(function(){
    staticNavURLs.push($(this).attr('href'));
});

var staticNavURLs = [];

$mobileMenu.find('a').each(function(){

staticNavURLs.push($(this).attr('href'));

});

Le console.log renvoie ceci:

(4) ["http://www.local/site_disabled/fr/home-static.html", "http://www.local/site_disabled/fr/flightlist-a-static.html", "http://www.local/site_disabled/fr/flightlist-d-static.html", "http://www.local/site_disabled/fr/companylist-static.html"]
0: "http://www.local/site_disabled/fr/home-static.html"
1: "http://www.local/site_disabled/fr/flightlist-a-static.html"
2: "http://www.local/site_disabled/fr/flightlist-d-static.html"
3: "http://www.local/site_disabled/fr/companylist-static.html"
length: 4

Comment ajouter des entrées clé+valeur (key+value) à un tableau?

var facetEntriesOffset = [];
$('.facet.dropdown', '#refinementFacets').each(function(){
    facetEntriesOffset.push({
        offsetLeft: $(this).offset().left,
        middle: $(this).outerWidth()/2
    });
});

var facetEntriesOffset = [];

$('.facet.dropdown', '#refinementFacets').each(function(){

facetEntriesOffset.push({

offsetLeft: $(this).offset().left,

middle: $(this).outerWidth()/2

});

Comment supprimer tous les éléments d’une tableau, sauf les N derniers?

arr = arr.slice(-1 * n);

1

arr = arr.slice(-1 * n);

Alternatively, modify the existing array with splice().

arr.splice(0, arr.length - n);

1

arr.splice(0, arr.length - n);

get closest number out of array

function closest (num, arr) {
    var curr = arr[0];
    var diff = Math.abs (num - curr);
    for (var val = 0; val < arr.length; val++) {
        var newdiff = Math.abs (num - arr[val]);
        if (newdiff < diff) {
            diff = newdiff;
            curr = arr[val];
        }
    }
    return curr;
}
array = [2, 42, 82, 122, 162, 202, 242, 282, 322, 362];
number = 112;
alert (closest (number, array));

function closest (num, arr) {

var curr = arr[0];

var diff = Math.abs (num - curr);

for (var val = 0; val < arr.length; val++) {

var newdiff = Math.abs (num - arr[val]);

if (newdiff < diff) {

diff = newdiff;

curr = arr[val];

}

return curr;

}

array = [2, 42, 82, 122, 162, 202, 242, 282, 322, 362];

number = 112;

alert (closest (number, array));

check if value exist or lies between particular values in array

var dataArr = [10, 20, 30, 50, 70, 80, 90, 100];

function _find(array, search) {
  var indexes = [],
      len = array.length,
      i,
      index = array.indexOf(search);

  if (~index) {
    return index;
  }

  if (search < array[0]) {
    return -1;  
  }

  for (i = 1; i < len; i++) {
    if (array[i] >= search) {
      return [i - 1, i];
    }    
  }

  return -1;
}


console.log(_find(dataArr, 22));

var dataArr = [10, 20, 30, 50, 70, 80, 90, 100];

function _find(array, search) {

var indexes = [],

len = array.length,

index = array.indexOf(search);

if (~index) {

return index;

}

if (search < array[0]) {

return -1;

}

for (i = 1; i < len; i++) {

if (array[i] >= search) {

return [i - 1, i];

}

return -1;

}

console.log(_find(dataArr, 22));

How to compare values between two arrays?

var A = [2, 12, 3, 42];
var B = [12, 42, 44, 12, 123];

var len = Math.max(A.length, B.length);
console.log(len)
for (var i = 0; i < len; i++) {
  console.log(A[i], B[i], A[i] === B[i])
}

var A = [2, 12, 3, 42];

var B = [12, 42, 44, 12, 123];

var len = Math.max(A.length, B.length);

console.log(len)

for (var i = 0; i < len; i++) {

console.log(A[i], B[i], A[i] === B[i])

}

Logic for checking in-between two numbers – Attention au code d’exemple qui fonctionne bien mais qui omet les accolades !!!.

var i; var y = 0; var val = 321; var zones = [0,150,300,400,600,800];
for (i = 0; i < zones.length; i++){
    if (val >= zones[i]){
        y = i;
    }
}
console.log('Value ' + val + ' is at position ' + y);

var i; var y = 0; var val = 321; var zones = [0,150,300,400,600,800];

for (i = 0; i < zones.length; i++){

if (val >= zones[i]){

y = i;

}

console.log('Value ' + val + ' is at position ' + y);

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