How to find the duplicates in an array using jquery

Question

I have a jQuery array:

var arr = $('input[name$="recordset"]');

I am getting the value of array like 8 or 6

If array values are repeating or duplicate I need to show "please do not repeat the values". If not I need to proceed further.

Using jQuery can anybody tell me how to find the duplicate values?

@kumar jQuery.unique will remove duplicate DOM elements. But there's no way that you have duplicate DOM elements when you use a selector. — Šime Vidas
– Šime Vidas, Commented Dec 3, 2010 at 14:38
I think what is OP is saying is that he's calling arr.val(), and it returns a number in the input; he wants to check for duplicate input values. — Matt Ball
– Matt Ball, Commented Dec 3, 2010 at 14:39

Sean Vieira · Accepted Answer · 2010-12-03 14:59:44Z

14

var unique_values = {};
var list_of_values = [];
$('input[name$="recordset"]').
    each(function(item) { 
        if ( ! unique_values[item.value] ) {
            unique_values[item.value] = true;
            list_of_values.push(item.value);
        } else {
            // We have duplicate values!
        }
    });

What we're doing is creating a hash to list values we've already seen, and a list to store all of the unique values. For every input the selector returns we're checking to see if we've already seen the value, and if not we're adding it to our list and adding it to our hash of already-seen-values.

edited Dec 3, 2010 at 14:59

answered Dec 3, 2010 at 14:41

Sean Vieira

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6 Comments

Šime Vidas Over a year ago

@Sean I recommend this: var val = $(item).val(); and then work with val instead of item.value. The reasoning behind this: the value of a form element is not always in its value attribute - it can be the text-content of the element, also.

Sean Vieira Over a year ago

@Šime - I cannot say I've ever encountered that. For my information, what form elements would this apply to?

Šime Vidas Over a year ago

@Sean I'll go check... give me a sec.

Šime Vidas Over a year ago

@Sean Using item.val is safe in Chrome. But I remember having an issue in an older version of IE. Unfortunately I only have IE9 beta here, so I cannot confirm it.

Sean Vieira Over a year ago

@Šime -- fair enough. I'll dig into it some more. Thanks for checking!

|

Senthil · Accepted Answer · 2012-02-03 04:07:55Z

2

Hope that below snippets will help if someone looks for this kind of requirement

var recordSetValues = $('input[name$="recordset"]').map(function ()    {
          return this.value;
      }).get();     
var recordSetUniqueValues = recordSetValues.filter(function (itm, i,    a) {
          return i == a.indexOf(itm);
      });
if (recordSetValues .length > recordSetUniqueValues.length)
      { alert("duplicate resource") }

answered Feb 3, 2012 at 4:07

Senthil

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Comments

Thiago Belem · Accepted Answer · 2010-12-03 14:38:56Z

1

// For every input, try to find other inputs with the same value
$('input[name$="recordset"]').each(function() {
   if ($('input[name$="recordset"][value="' + $(this).val() + '"]').size() > 1)
      alert('Duplicate: ' + $(this).val());
});

answered Dec 3, 2010 at 14:38

Thiago Belem

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2 Comments

Šime Vidas Over a year ago

The API says that unique() only works for arrays of DOM elements.

kumar Over a year ago

Thanks Tiu Talk.. but my array is allways checking with 0 its not alowing me to check with other values.. like 1 2 3 thanks

Needhi Agrawal · Accepted Answer · 2014-09-17 06:08:32Z

1

$('form').submit(function(e) {

    var values = $('input[name="recordset[]"]').map(function() {
      return this.value;
    }).toArray();

    var hasDups = !values.every(function(v,i) {
      return values.indexOf(v) == i;
    });
    if(hasDups){
       // having duplicate values
       alert("please do not repeat the values");
       e.preventDefault();
    }

});

answered Sep 17, 2014 at 6:08

Needhi Agrawal

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