How to remove partial duplicate values in jquery array

Question

I have a single level array of key/value pairs, like this:

var user_filters= ['color=blue', 'size=small', 'shape=circle', 'size=large', 'shape=square']

I need a function to perform the following:

find all duplicate keys
replace the first occurrence of the key/value pair with the second occurrence
delete the second occurrence

In this case, it would produce the following result:

user_filters= ['color=blue', 'size=large', 'shape=square']

Something like...

function update_array(){
   $.each(user_filters, function(i){
      var key = this.split('=')[0];
      if(key is second occurrence in user_filters)
      {
          var index = index of first occurrence of key
          user_filters[index] = user_filters[i];
          user_filters.splice(i,1); 
      }

   });
}

What is the best way to do this? Thanks!

"What's the best way to do this?" Ah, the age old question on SO. — Erick Smith
– Erick Smith, Commented Feb 20, 2017 at 14:39
What if the collection contains 3 duplicate keys? Then do you want the last? — dana
– dana, Commented Feb 20, 2017 at 14:43

Z-Bone · Accepted Answer · 2017-02-20 14:39:00Z

4

I would keep the data in an object and this way any duplicate will automatically overwrite the previous entry..

See this for example:

var user_filters= ['color=blue', 'size=small', 'shape=circle', 'size=large', 'shape=square'];
var object = {};

for (var i = 0; i < user_filters.length; i++) {
  var currentItem = user_filters[i].split('=');
  var key = currentItem[0];
  var value = currentItem[1];
  object[key] = value;
}

console.log(object);

answered Feb 20, 2017 at 14:39

Z-Bone

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4 Comments

ibrahim mahrir Over a year ago

Not the output user expects!

Z-Bone Over a year ago

@ibrahimmahrir He asked what's the best way to do it.. Meaning he would like to see additional approaches..

p1xelarchitect Over a year ago

This is perfect. Nicely done. Solves my problem, thank you!

Z-Bone Over a year ago

Sure thing.. Glad I could help :)

ibrahim mahrir · Accepted Answer · 2017-02-20 14:40:37Z

0

You can use a hash object to get the key-value pairs without duplicates and then transform the hash object back into an array like this:

function removeDuplicates(arr) {
  var hash = arr.reduce(function(h, e) {
    var parts = e.split("=");
    h[parts[0]] = parts[1];
    return h;
  }, {});
  
  return Object.keys(hash).map(function(key) {
    return key + "=" + hash[key];
  });
}

var user_filters = ['color=blue', 'size=small', 'shape=circle', 'size=large', 'shape=square'];

console.log(removeDuplicates(user_filters));

answered Feb 20, 2017 at 14:40

ibrahim mahrir

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Comments

baao · Accepted Answer · 2017-02-20 14:45:47Z

0

You could use a Map which does the unique/overriding automatically, and is able to get you an array back in case you need it

var user_filters= ['color=blue', 'size=small', 'shape=circle', 'size=large', 'shape=square'];

var m = new Map(user_filters.map(v => v.split("=")));
console.log([...m.entries()].map(v => v.join("=")));

edited Feb 20, 2017 at 14:45

answered Feb 20, 2017 at 14:41

baao

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1 Comment

ibrahim mahrir Over a year ago

Not the output user expects!

Meena Pintu · Accepted Answer · 2017-02-20 14:54:04Z

0

It would be better to iterate from back of array , thus for every unique key you need to keep a variable true or false (initially false). so if true mean already occurred so deleted it else keep it and make its variable true .

It is much more better approach then your current . you don't have to keep last index and swapping then deleting.

answered Feb 20, 2017 at 14:54

Meena Pintu

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Comments

ABHIJITH GM · Accepted Answer · 2017-02-20 15:17:09Z

0

You may convert to json and then back to the array format you want . IN the below code you get the result object in the format you want.

var user_filters= ['color=blue', 'size=small', 'shape=circle', 'size=large', 'shape=square'];

function toJson(obj){
var output = {};
$.each(obj, function(i){
    var keyvalPair = this.split('=')
  var key = keyvalPair[0];
  output[key]= keyvalPair[1];
});
return output;
}
function toArray(obj){
var output = [];
$.each(obj, function(i){
    output.push(i+"="+obj[i]);
});
return output;
 }
var result = toArray(toJson(user_filters));
 console.log(result);

answered Feb 20, 2017 at 15:17

ABHIJITH GM

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