Create an array in jquery and check if it's an element

Question

After getting some data using ajax & json i've got this function

    if(data.length != 0) {
        var arreglo = new Array();
        $.each(data, function(index, data) {
            if (jQuery.inArray(data.id, arreglo) == -1) {
                arreglo.push(data.id);
                $("#envivo").append("<li>Titulo: " + data.titulo + " Link: " + data.link + " Fuente: " + data.fuente + "</li>");
            }
        });
    }
}
$(document).ready(function() {
    var fecha = Math.round((new Date()).getTime() / 1000);
    setInterval(function() {
        $.ajax({
            data: "fecha="+fecha,
            type: "GET",
            dataType: "json",
            url: "data.php",
            success: function(data){
                restults(data);
            }
        });
    }, 5000);
});

What i'm trying to do

Check if any data it's retrieved from ajax
Create an array to store data.id
Loop inside the data from ajax
Check if data.id it's in array created in [2]
If id it's not in array, i save it into and apped some data

step 4 it's not working and part of the 5 (saving into array)

Any ideas?

Thanks in advance

Nope, any error messages... It keeps appending again and again so i think the array check it's wrong A've added my whole js. — Zuker
– Zuker, Commented Apr 13, 2011 at 14:55

Paul Perigny · Accepted Answer · 2011-04-13 14:40:01Z

1

The inArray function uses the identity compare operator (===).

This will cause problems if the data returned the id as a string, but you are interpreting is as a number.

"9" ==== 9 <- False

"9" == 9 <- True

answered Apr 13, 2011 at 14:40

Paul Perigny

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11 Comments

Zuker Over a year ago

I'm using the inArray to check if the data.id it's on the array... is it wrong to use == -1 ?

Paul Perigny Over a year ago

That part is correct, but in the data sample you provided the id is actually "17", not 17. the inArray function will not match 17 and "17" as they are not the same data type. Either send the data as a number, or loop thru the data that was returned and parseInt to force it to the correct data type.

Zuker Over a year ago

Hi paul. How can i send the data fine? i'm using json encode... take a look at data.php $fecha = $_GET['fecha']; $feed = array(); $result = mysql_query("SELECT * FROM envivo WHERE fecha >= '".$fecha."' ORDER BY fecha DESC"); $existe = mysql_num_rows($result); if ($existe != 0) { while ($data = mysql_fetch_array($result)) { $jsondata = array(); $jsondata['id'] = $data['id']; $jsondata['titulo'] = $data['titulo']; $jsondata['link'] = $data['link']; $jsondata['fuente'] = $data['fuente']; $feed[] = $jsondata; } echo json_encode($feed); } Thanks again

Guffa Over a year ago

That should not be a problem, as the values added to the array is the same type as the values used to search in the array.

Zuker Over a year ago

So where it's the problem with the id?

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Community · Accepted Answer · 2020-06-20 09:12:55Z

0

I have tried your code, and it works just fine:

http://jsfiddle.net/Jfq6d/

You have to check that the data that you get actually looks the way that you expect. You can for example use the Net tab in the FireBug addon in Firefox to examine the response that you get in the AJAX call.

Edit:

As you want to reuse the function, you have to create the array outside the function:

var arreglo = [];

function restults(data) {
  if(data.length != 0) {
    $.each(data, function(index, data) {
      if (jQuery.inArray(data.id, arreglo) == -1) {
        arreglo.push(data.id);
        $("#envivo").append("<li>Titulo: " + data.titulo + " Link: " + data.link + " Fuente: " + data.fuente + "</li>");
      }
    });
  }
}

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Apr 13, 2011 at 14:33

Guffa

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6 Comments

Zuker Over a year ago

Data it's like this [{"id":"17","titulo":"Radio LocalStrike tiene un nuevo programa, Ranking Fusa","link":"http:\/\/www.localstrike.net\/radio\/noticias-55\/radio_localstrike_tiene_un_nuevo_programa_ranking_fusa-1283","fuente":"LocalStrike"}]

Guffa Over a year ago

@Zuker: I tried with data like that, and it still works: jsfiddle.net/Jfq6d/1 The conclusion is that the data is actually not like that, and you have to check what the data really looks like.

Zuker Over a year ago

Guffa please try to replicate that using the full code with the setInterval so you can certainly check that id's aren replicating

Guffa Over a year ago

@Zuker: The method doesn't add any duplicates, but if you run it more than once it will not keep from adding items that was added previously. If you want it to remember the id's from one execution to the next, you have to create the array outside the function.

Paul Perigny Over a year ago

@Guffa: One problem with the inArray method is that it runs the native indexOf function if available in your browser. That function may not use the === operator and so the comparison function ends up browser specific.

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