Array not showing length

Question

Been trying for about an hour now, can't get my array to show its length upon a button press. It did show its length at one attempt, but it was a totally different amount to the amount of elements in the array. I read somewhere that it happens that way sometimes, and has something to do with undefined elements. But now it isn't showing any alerts at all.

var fruits("Banana", "Apple", "Orange")

function myFunction() {
  alert(fruits.length)
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<!DOCTYPE html>
<html>

<head>

  <body>
    <script>
      src = "https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js" >
    </script>
    <script src="Arrays.js">
    </script>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
    <script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
</head>
</head>
<button id="lengthbutton" onclick="myFunction()"> Click me to find out length </button>
</body>

</html>

@JoshuaDuxbury , I've linked the source in between the head tags — BrownEyedNinja, Jul 20 '17 at 08:49
javascript [array](https://www.w3schools.com/js/js_arrays.asp) check this — Durga, Jul 20 '17 at 08:51
@Durga thanks for the suggestion. Should've known to check W3schools. — BrownEyedNinja, Jul 20 '17 at 08:54
If one of the answers below fixes your issue, you should accept it (click the check mark next to the appropriate answer). That does two things. It lets everyone know your issue has been resolved to your satisfaction, and it gives the person that helps you credit for the assist. [See here](http://meta.stackexchange.com/a/5235) for a full explanation. — Joshua Duxbury, Jul 20 '17 at 08:56

score 4 · Accepted Answer · answered Jul 20 '17 at 08:49

If you want to declare an array using () you need to use new Array():

var fruits = new Array("Banana", "Apple", "Orange")

function myFunction() {
  alert(fruits.length)
}

<button id="lengthbutton" onclick="myFunction()"> Click me to find out length </button>

score 2 · Answer 2 · answered Jul 20 '17 at 08:56

2

var fruits = new Array("Banana","Apple", "Orange" );
var fruitsArr = ["Banana","Apple", "Orange" ];

function myFunction(arr) {
console.log(arr.length)
}

myFunction(fruits)
myFunction(fruitsArr)

You can create an array using array literal i.e [] or you can use new Array() to create an array.

answered Jul 20 '17 at 08:56

Durga

15,263
2
28
52

Thanks, the square bracket option came in handy. – BrownEyedNinja Jul 20 '17 at 09:05
@draneol here you can get some [difference](https://stackoverflow.com/a/931875/3551786) – Durga Jul 20 '17 at 09:12
Thanks, that was helpful. – BrownEyedNinja Jul 20 '17 at 09:14

Geeky Ninja · Answer 3 · 2017-07-20T08:54:38.197

1

Your array declaration is JavaScript code is incorrect. It should be like.

var fruits = ["Banana","Apple","Orange"]

var fruits = ["Banana", "Apple", "Orange"];

function myFunction() {
  alert(fruits.length)
}

<button id="lengthbutton" onclick="myFunction()">Find Length of Array</button>

edited Jul 20 '17 at 08:54

answered Jul 20 '17 at 08:53

Geeky Ninja

6,002
8
41
54

1

@draneol Its the way you are declaring your array, var fruits ("Banana","Apple", "Orange") is not the correct way of declaring array. Instead, you can declare array by two ways 1) using [ ] brackets (as I have used in example) 2) or using new keyword e.g. var fruits = new Array('a','b'). – Geeky Ninja Jul 20 '17 at 09:02

score 0 · Answer 4 · answered Jul 20 '17 at 08:48

0

The array literal syntax in JavaScript uses square brackets:

var fruits = [ "Banana","Apple", "Orange" ]

answered Jul 20 '17 at 08:48

hellojeffhall

291
3
8

thanks for the suggestion, still isn't working after adding square brackets :( – BrownEyedNinja Jul 20 '17 at 08:51
1

You might have added just square brackets, have you changed the assignments also ? – Nandan Bhat Jul 20 '17 at 08:52
Good point, I wasn't explicit about that but the equals sign is very important. Good eye, Nandan! – hellojeffhall Jul 20 '17 at 08:53

score 0 · Answer 5 · answered Jul 20 '17 at 08:50

0

var fruits = ["Banana","Apple", "Orange"]

Your code has something wrong.

answered Jul 20 '17 at 08:50

chen lin

21
4

1

It helps by describing what the problem was. – Tez Wingfield Jul 20 '17 at 08:55

score 0 · Answer 6 · answered Jul 20 '17 at 09:19

You need to use () with new Array() or you can use [] if you do not want to declare it explicitly. e.g.

var fruits = new Array("Banana", "Apple", "Orange")

OR

var fruits = ["Banana", "Apple", "Orange"]

var fruits = ["Banana", "Apple", "Orange"]

function myFunction() {
  alert(fruits.length)
}

<button id="lengthbutton" onclick="myFunction()"> Click me to find out length </button>

OR

var fruits = new Array("Banana", "Apple", "Orange")

function myFunction() {
  alert(fruits.length)
}

<button id="lengthbutton" onclick="myFunction()"> Click me to find out length </button>

Array not showing length

6 Answers6