insertItem

Category:Variables

insertItem(list, index, item)

Category: Variables

Inserts the item into the array at the specified index position.

In real life you sometimes need to add items at various positions in a list, and make the list larger. insertItem(list, index, item) makes the "list" one larger and inserts the "item" at the specified index position (moving other items to the right). The index must be a valid index position in the list or you may get unexpected results.

Examples

// List of favorite foods.
var myFavoriteFoods=["pizza","steak"];
console.log(myFavoriteFoods + " length=" +myFavoriteFoods.length);
insertItem(myFavoriteFoods, 1, "artichokes");
console.log(myFavoriteFoods + " length=" +myFavoriteFoods.length);
insertItem(myFavoriteFoods, 4, "shrimp");
console.log((myFavoriteFoods + " length=") +myFavoriteFoods.length);

Example: Fibonacci Generate the first 10 numbers in the fibonacci sequence.

// Generate the first 10 numbers in the fibonacci sequence.
var fibonacci=[1,1];
var nextTerm=0;
for (var i=3; i<=10; i++) {
  nextTerm=fibonacci[i-2]+fibonacci[i-3];
  insertItem(fibonacci, i, nextTerm);
}
console.log(fibonacci);

Syntax

insertItem(list, index, item)

Parameters

Name	Type	Required?	Description
list	variable name	Yes	The variable name of the list (array) you want to insert the item into.
index	number	Yes	The index position you want to insert the item at.
item	any type	Yes	The number or string item to be inserted into the list.

Returns

No return value.

Tips

List(array) manipulation functions include: appendItem(list, item), insertItem(list, index, item) and removeItem(list, index).
Multiple calls to insertItem() can be slow because to expand the list, Javascript needs to create a new list one item larger and then copy all the items over before instering the new item at the end. If possible it is better to create the list intially large enough for all the possible items and list[index] to add new items at specific positions.

Found a bug in the documentation? Let us know at documentation@code.org

Syntax

insertItem(list, index, item)

Found a bug in the documentation? Let us know at documentation@code.org