I need to remove all elements in an array that do not contain "IN" in uppercase exactly like that.

How I thought of doing this was to traverse the array with a for loop and write all values that contain IN to another array.

Is there a way I can do it without writing to a new array and just removing those items that don't match from the current array?

Here is the code for how I was planning on doing it:

arrTwo = [];

for(var i = 0; i<arr.length; i++){
    if(arr[i].indexOf('IN') > -1) arrTwo.push[arr[i]];
}

I need to remove all elements in an array that do not contain "IN" in uppercase exactly like that.

How I thought of doing this was to traverse the array with a for loop and write all values that contain IN to another array.

Is there a way I can do it without writing to a new array and just removing those items that don't match from the current array?

Here is the code for how I was planning on doing it:

arrTwo = [];

for(var i = 0; i<arr.length; i++){
    if(arr[i].indexOf('IN') > -1) arrTwo.push[arr[i]];
}

• javascript
• jquery
• arrays

• There is filter function defined for the array object which you can use. It will create a new filtered array though – Andrei Commented Jun 13, 2014 at 22:39

3 Answers 3

You can use ES5 filter method:

arr = arr.filter(function(s){
    return ~s.indexOf("IN");
});

And using ES6 arrow functions, it can be simplified to:

arr = arr.filter(s=>~s.indexOf("IN"));

Here's a really good thread that has a couple of ways to acplish this. If you do not delete the element of the array in the correct manner, you that element will be undefined rather than actually deleted. The .spilce() method is what you want to look into.

Deleting array elements in JavaScript - delete vs splice

I would do it using the splice() method:

var testArray = [ 'this one contains IN', 'this one does not' ];

function filterArray ( arr ) {
    var i = arr.length;
    //-- Loop through the array in reverse order since we are modifying the array.
    while (i--) {
        if (arr[i].indexOf('IN') < 0) {
            //-- splice will remove the non-matching element
            arr.splice(i, 1);
        }
    }
}

filterArray( testArray );

document.body.innerText = JSON.stringify(testArray);

JSFiddle: http://jsfiddle/5DW8L/1/