Remove empty positions from an array

Question

Remove empty positions from an array

Asked 10 years ago

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7

I’m passing a array via GET for PHP and then send it to the client side (Javascript). When I receive it it looks like this:

m_prod = [5,,,,,,,,6,,,,,,];

In other words, it is including a space in the positions that does not contain a value! How can I remove these spaces in Javascript?

<?php
    $m_prod = trim($_GET['m_prod']);
    print("<SCRIPT language=javascript> m_prod = \"$m_prod\"; </SCRIPT>");
?>

Just want to remove spaces? Or also reduce the array size?

– CesarMiguel

2014/11/19 at 14:50
Well, at first I would like to remove the spaces, because then the array would be only with m_prod = [5,6];

– Alexandre

2014/11/19 at 14:51
Then I guess you already have the answer down

– CesarMiguel

2014/11/19 at 14:52
@Alexandre can explain better where this array comes from? comes from PHP?

– Sergio

2014/11/19 at 15:22
Yes the array comes from PHP!

– Alexandre

2014/11/19 at 15:24
1

@Alexandre then the interesting is to see your PHP code to solve the problem at source. You have access to PHP?

– Sergio

2014/11/19 at 15:26
1

@Sergio already modify the code to show how enough my php!

– Alexandre

2014/11/19 at 15:29

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2 answers

13

You can use the function filter, as follows:

var m_prod = [5, , , , , , , , , ,6 , , , ];

var resultado = m_prod.filter(function(ele){
  return ele !== undefined;
});

console.log(resultado);  // [5,6]

1

Just what I needed! Thanks @Brunocalza

– Alexandre

2014/11/19 at 14:56
So @Brunocalza, it goes through the filter but still keeps the positions empty! It’s like it doesn’t just return the values!

– Alexandre

2014/11/19 at 15:19
sorry @Alexandre, I don’t understand. keep in mind that m_prod will not be changed.

– Bruno Calza

2014/11/19 at 15:23
My mistake, instead of using undefined use the "" so returns the fields I need!

– Alexandre

2014/11/19 at 15:24

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by Sergio • **133,294** points · Answer 1 · 2014-11-19T15:54:05+00:00

If the problem comes from PHP I think it should solve in PHP.

To filter an array of empty elements:

$m_prod = array_filter($m_prod);

In case there are numbers inside the array then we have to be extra careful because the 0 validates as false and is removed from the array. So you can do:

$m_prod = array_filter($m_prod, function($value) {
  return !empty($value) || $value === 0;
});

To pass this to Javascript you can render like this:

echo '<script>';
echo 'm_prod = '.json_encode($m_prod);
echo '</script>';