Removing duplicates entries from a multidimensional php array [duplicate]

Question

I have a the following array structure how can I process it in such a way so as to remove all the successive occurrences of change_status. Please see the array below and then what I want to achieve.

$a=array( 
    "0" => array(  "status_change" => "start", "clock_status" => "1" ),
    "1" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "2" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "3" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "4" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "5" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "6" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "7" => array(  "status_change" => "start", "clock_status" => "1" ),
    "8" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "9" => array(  "status_change" => "start", "clock_status" => "1" ),
    "10" => array(  "status_change" => "start", "clock_status" => "1" ),
    "11" => array(  "status_change" => "start", "clock_status" => "1" ),
    "12" => array(  "status_change" => "start", "clock_status" => "1" )
    );

After processing the above array I would like to have the following

$a=array( 
    "0" => array(  "status_change" => "start", "clock_status" => "1" ),
    "1" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "7" => array(  "status_change" => "start", "clock_status" => "1" ),
    "8" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "9" => array(  "status_change" => "start", "clock_status" => "1" )
    );

Any ideas will be appreciated. I do have a code that deals with the one dimensional array but this one is confusing me and I am a bit slow when dealing with the arrays.

You asked this question not long ago. What happened to answer here? — Chibueze Opata
– Chibueze Opata, Commented Jul 18, 2013 at 9:04
this is not really a "array remove duplicate"... cause he want to remove duplicate entry with a logic... removing all the duplicates the expected results will be an array of 2 items, and not what he want. — MiPnamic
– MiPnamic, Commented Jul 18, 2013 at 9:16
Hi @Chibueze Opata the other function worked but i want another function that can work on the multidimensional arrays — Abbasi
– Abbasi, Commented Jul 18, 2013 at 9:26

Jon · Accepted Answer · 2013-07-18 09:02:32Z

2

Iterate over the array while keeping track of the previous element. If the current element is equal to the previous, remove it:

$previous = null;
foreach ($a as $key => $value) {
    if ($value === $previous) {
        unset($a[$key]);
    }
    $previous = $value;
}

Note that I have chosen to use the identity operator === to compare the previous and current value because this looks the most fitting for the data you give. If the data format can vary you would need to use a looser form of comparison.

answered Jul 18, 2013 at 9:02

Jon

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14 Comments

insanebits Over a year ago

will this really remove all duplicates? or only those which goes in a row?

Prasanth Bendra Over a year ago

I think you missed the line to assign value to $previous in loop

Jon Over a year ago

@insanebits: Those in a row, as the question says "successive duplicates".

insanebits Over a year ago

Oh sorry missed this one :)

Abbasi Over a year ago

Thank you very much Jon :-) worked like a charm :) any ideas about how to do this using recursion?

|

Loken Makwana · Accepted Answer · 2013-07-18 09:13:48Z

Please check with following code

$source=array( 
    "0" => array(  "status_change" => "start", "clock_status" => "1" ),
    "1" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "2" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "3" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "4" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "5" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "6" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "7" => array(  "status_change" => "start", "clock_status" => "1" ),
    "8" => array(  "status_change" => "stop", "clock_status" => "2" ),
    "9" => array(  "status_change" => "start", "clock_status" => "1" ),
    "10" => array(  "status_change" => "start", "clock_status" => "1" ),
    "11" => array(  "status_change" => "start", "clock_status" => "1" ),
    "12" => array(  "status_change" => "start", "clock_status" => "1" )
    );

function reduce_successive(&$source) {      
    $prev_status = 'none';
    foreach($source as $key=>$item) {
        if($item['status_change'] == $prev_status) {
            unset($source[$key]);
        } else {
            $prev_status = $item['status_change'];
        }
    }
}
reduce_successive($source);
var_dump( $source );

Serge Velikan · Accepted Answer · 2013-07-18 09:15:33Z

0

Of course you can use the object and array_unique for this kind of task:

<?php
class Test
{
    public $key;
    public $value;
    private $group;
    public function __construct($k,$v,$group=0)
    {
        $this->key=$k;
        $this->value=$v;
            $this->group=$group;
    }
    public function __toString()
    {
        return$this->key."_".$this->value."_".$this->group;
    }
}
$arr=array();
$arr[]=new Test("start",1);
$arr[]=new Test("stop",2);
$arr[]=new Test("stop",2);
$arr[]=new Test("stop",2);

$arr=array_unique($arr);
print_r($arr);
?>

And for each "start" key you can increment your group iterator.

edited Jul 18, 2013 at 9:15

answered Jul 18, 2013 at 9:09

Serge Velikan

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