Compare an array based on previous value of the array

Question

I have an array that looks like this:

Array ( 
    [0] => Array (  
        [START] => COI-COK 
        [RETURN] => CAI - DEL 
    ) 
    [1] => Array ( 
        [START] => COK - AMM 
        [RETURN] => CAI - DEL 
    ) 
)

I want to check if both 'start' and 'end' values of previous and current array are same or not. If not then, print some value. How can I do it?

This is my attempt:

foreach($data as $datas)
{     
    $old_start  = $datas['START'];
    $old_return = $datas['RETURN'];

    ...

    if( ($old_start == $datas['START']) && ($old_return == $datas['RETURN']))
    {

    }
    else
    {

    }
}

But it didn't work because all the time old_start value will be equal to $datas['START'].

print_r($data) shows this output:

Array ( 
    [0] => Array ( 
        [Sl] => 2 
        [TRAVELDAY] => 2015-11-11 
        [RETURNDAY] => 2015-11-27 
        [START] => COI-COK 
        [RETURN] => CAI - DEL 
    ) 
    [1] => Array ( 
        [Sl] => 1 
        [TRAVELDAY] => 2015-11-11 
        [RETURNDAY] => 2015-11-27 
        [START] => COK - AMM 
        [RETURN] => CAI - DEL 
    ) 
)

@AjithN: No problem; in future, please do make sure to format your questions neatly. Tip: you can add header('Content-Type: text/plain;charset=utf8'); at the very top of your script to see the output produced exactly as it is. — Amal
– Amal, Commented Nov 6, 2015 at 10:52

syck · Accepted Answer · 2015-11-06 11:42:25Z

2

You have to put the assignment after the comparison, not before:

$old_start = '';
$old_return = '';
foreach($data as $datas)
{     
     //....
     if($old_start=='' || $old_start == $datas['START'] && $old_return == $datas['RETURN'])
     {
         //....
     }
     else
     {
         //code to be executed
     }

     $old_start = $datas['START'];
     $old_return = $datas['RETURN'];
}

edited Nov 6, 2015 at 11:42

answered Nov 6, 2015 at 10:30

syck

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7 Comments

Amal Over a year ago

$old_start won't be initialized inside the loop - this will just throw an Undefined Variable error.

syck Over a year ago

@AmalMurali If you can see the edit history, you will see that I edited it in before you posted your comment. Thanks for the constructive downvote.

syck Over a year ago

@AjithN The code in the else path? You only have to check whether for example $old_start==''.

Amal Over a year ago

@syck: Apparently yes, I've rescinded my downvote and made it an upvote.

syck Over a year ago

@AjithN edited the code so it won't trigger on first loop.

|

Amit Rajput · Accepted Answer · 2015-11-06 10:40:22Z

1

Try like this..

$old_start = "";
$old_return = "";

foreach($data as $datas)
{     

    if( ($old_start == $datas['START']) && ($old_return == $datas['RETURN']))
    {
        //true code to be executed
    }
    else
    {
        //false code to be executed
    }

    $old_start = $datas['START'];
    $old_return = $datas['RETURN'];
}

answered Nov 6, 2015 at 10:40

Amit Rajput

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1 Comment

Vivek Tankaria Over a year ago

This will go in false for 0 key array. Which is not to be tested.

Amarnasan · Accepted Answer · 2015-11-06 10:50:26Z

1

foreach($data as $sample) {
    if (!isset($temp)) {
        $temp = $sample;
    } else {
        if ($temp['START']==$sample['START'] && $temp['RETURN']==$sample['RETURN']) {
            ; //WHATEVER EQUAL
        } else {
            ; //WHATEVER NOT EQUAL
        }
        $temp = $sample;
    }
}

edited Nov 6, 2015 at 10:50

answered Nov 6, 2015 at 10:38

Amarnasan

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Comments

Vivek Tankaria · Accepted Answer · 2015-11-06 10:42:49Z

$array = Array ( 0 => Array ( "START" => "COI-COK", "RETURN" => "CAI - DEL"), 1 => Array ( "START" => "COK - AMM","RETURN" => "CAI - DEL" ),2=> Array ( "START" => "COK - AMM","RETURN" => "CAI - DEL" ) );

$old_start = "";
$old_return = "";
foreach($array as $ak=>$av){
    if(empty($old_start)){
        $old_start = $av['START'];
        $old_return = $av['RETURN'];
    }else{
        if($old_start == $av['START'] && $old_return == $av['RETURN']){
            echo "SAME\n";
        }else{
            echo "Varies\n";
        }

        $old_start = $av['START'];
        $old_return = $av['RETURN'];
    }
}

//Output 
Varies //key 1 will not match with key 0 value
Same   // key 2 will not match with key 1 value

Hope this clears your logic, add as many array value you want , I modified your array from 2 to 3 to show the difference. This will compare n with n+1 and show the result.

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