if I have an array like:
var myArray = [
{
'color':'red',
'name': 'redName'
},
{
'color':'blue',
'name': 'blueName'
},
{
'color':'green',
'name': 'greenName'
},
{
'color':'yellow',
'name': 'yellowName'
},
];
How do I get the index of say, "blue"?
9 Answers
If you're already using ECMAScript 5 in your code you can use that:
myArray
.map(function (element) {return element.color;})
.indexOf('blue');
Note that the support to these functions is a quite limited (they don't work on Internet Explorer 8).
Also, if you're in the future, and you're using ES6 you can do that:
myArray.map((el) => el.color).indexOf('blue');
That's the same as above, but smaller.
for(var i = 0; i < myArray.length; i++) {
if(myArray[i].color === 'blue') {
return i;
}
}
There's no "clean" way unless you want to involve a third-party library. Underscore is a good one for stuff like this.
I know this is super old but Javascript es6 has an awesome method Array.prototype.findIndex(), so you could just do:
let index = myArray.findIndex((item) => item.color === 'blue');
// value of index will be "1"
That's not a multi-dimensional array (or even a jagged array, which is used instead of multi-dimensional arrays in Javascript as they don't exist). That is an array of objects.
You can loop through the items in the array:
var index;
for (var i = 0; i < myArray.length; i++) {
if (myArray[i].color == 'blue') {
index = i;
break;
}
}
Now the variable index contains the value 1, with your given example.
You can use .findIndex() method
In your case
var findeMe = "blue";
myArray.findIndex(function(row){
return row.color == findMe;
});
I hope it help.
I'm guessing you mean from your example to return "1"? Here is a function for you...
<script type='text/javascript'>
var myArray = [
{
'color':'red',
'name': 'redName'
},
{
'color':'blue',
'name': 'blueName'
},
{
'color':'green',
'name': 'greenName'
},
{
'color':'yellow',
'name': 'yellowName'
},
];
function getIndexOf(a,v) {
var l = a.length;
for (var k=0;k<l;k++) {
if (a[k].color==v) {
return k;
}
}
return false;
}
alert (getIndexOf(myArray,'blue'));
</script>
For example like this:
Array.prototype.objIndexOf = function(val) {
var cnt =-1;
for (var i=0, n=this.length;i<n;i++) {
cnt++;
for(var o in this[i]) {
if (this[i].hasOwnProperty(o) && this[i][o]==val) return cnt;
}
}
return -1;
}
var myArray = [
{
'color':'red',
'name': 'redName'
},
{
'color':'blue',
'name': 'blueName'
},
{
'color':'green',
'name': 'greenName'
},
{
'color':'yellow',
'name': 'yellowName'
},
];
alert(myArray.objIndexOf('blue'))
Iterate over the array, looking for the value inside each element object. Raw JavaScript doesn't give you a whole lot to work with.
In my case, I have built my own functions because I wanted the loop to stop at the first element found.
That's why the solutions with map were not working to this case as they are creating a new array.
var i = 0;
while (i < myArray.length) {
if (myArray[i].color == 'blue') {
return i;
}
i++
}
return -1