Most efficient way to replace empty values in an array

Question

Is there a better way of doing this PHP code? What I'm doing is looping through the array and replacing the "title" field if it's blank.

if($result)
{
    $count = 0; 

    foreach($result as $result_row)
    {
        if( !$result_row["title"] )
        {
            $result[$count]["title"] = "untitled";
        }

        $count++;
    }
}

Where $result is an array with data like this:

Array
(
        [0] => Array
                (
                        [title] => sdsdsdsd
                        [body] => ssdsd
                )

        [1] => Array
                (
                        [title] => sdssdsfds
                        [body] => sdsdsd
                )


)

I'm not an experienced PHP developer, but I guess that the way I've proposed above isn't the most efficient?

Thanks

I'd say this is probably plenty fast unless you have a bazillion rows (in which case you'd probably have some other problems). — Jani Hartikainen
– Jani Hartikainen, Commented Jan 7, 2011 at 21:13

Surreal Dreams · Accepted Answer · 2011-01-07 21:27:22Z

3

if($result) {
    foreach($result as $index=>$result_row) {
        if( !$result_row["title"] ) {
            $result[$index]["title"] = "untitled";
        }
    }
}

You don't need to count it. It's efficient.

edited Jan 7, 2011 at 21:27

Surreal Dreams

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answered Jan 7, 2011 at 21:17

profitphp

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2 Comments

Alix Axel Over a year ago

What is the if($result) doing in there? What if $result is a string? I could understand if (is_array($result)) but this doesn't compute..

profitphp Over a year ago

yes, is_array would be better. That was just a copy and paste from his original and i didn't think of changing that part.

webbiedave · Accepted Answer · 2011-01-07 21:35:23Z

3

if ($result)
{
    foreach($result as &$result_row)
    {
        if(!$result_row['title'])
        {
            $result_row['title'] = 'untitled';
        }
    }
}

Also, you may want to use something other than a boolean cast to check the existence of a title in case some young punk director releases a movie called 0.

You could do something like if (trim($result_row['title']) == '')

edited Jan 7, 2011 at 21:35

answered Jan 7, 2011 at 21:23

webbiedave

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3 Comments

NikiC Over a year ago

+1 for correct reference approach. Though trim == '' won't help against 0. For PHP '0' == ''. You would need to ===.

webbiedave Over a year ago

@nikic: '0' == '' returns false while 0 == '' returns true. $result_row['title'] will be a string so this will work fine.

NikiC Over a year ago

Wow, seems like PHPs type juggling finally did drive me crazy... Always thought that would yield true.

Surreal Dreams · Accepted Answer · 2011-01-07 21:23:42Z

1

Mixing in a little more to @Luke's answer...

if($result) {
  foreach($result as &$result_row) {  // <--- Add & here
    if($result_row['title'] == '') {
      $result_row['title'] = 'untitled';
    }
  }
}

The key is the & before $result_row in the foreach statement. This make it a foreach by reference. Without that, the value of $result_row is a copy, not the original. Your loop will finish and do all the processing but it won't be kept.

The only way to get more efficient is to look at where the data comes from. If you're retrieving it from a database, could you potentially save each record with an "untitled" value as the default so you don't need to go back and put in the value later?

answered Jan 7, 2011 at 21:23

Surreal Dreams

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2 Comments

netcoder Over a year ago

||= is still not valid. ;) And assigning the value as reference won't make it more efficient really.

Surreal Dreams Over a year ago

Just saw Luke's comments so I replaced the ||= operator. Explains why I couldn't find it for PHP, no such animal.

Alix Axel · Accepted Answer · 2011-01-07 22:22:23Z

Another alternative could be json_encode + str_replace() and then json_decode():

$data = array
(
    0 => array
    (
        'title' => '',
        'body' => 'empty',
    ),

    1 => array
    (
        'title' => 'set',
        'body' => 'not-empty',
    ),
);

$data = json_encode($data); // [{"title":"","body":"empty"},{"title":"set","body":"not-empty"}]
$data = json_decode(str_replace('"title":""', '"title":"untitled"', $data), true);

As a one-liner:

$data = json_decode(str_replace('"title":""', '"title":"untitled"', json_encode($data)), true);

Output:

Array
(
    [0] => Array
        (
            [title] => untitled
            [body] => empty
        )

    [1] => Array
        (
            [title] => set
            [body] => not-empty
        )
)

I'm not sure if this is more efficient (I doubt it, but you can benchmark it), but at least it's a different way of doing the same and should work fine - you have to care about multi-dimensional arrays if you use the title index elsewhere thought.

Derek Downey · Accepted Answer · 2011-01-07 21:25:02Z

0

Perhaps array_walk_recursive:

<?php 
$myArr = array (array("title" => "sdsdsdsd", "body" => "ssdsd"), 
              array("title" => "", "body" => "sdsdsd")  );
array_walk_recursive($myArr, "convertTitle");
var_dump($myArr);

function convertTitle(&$item, $key) {
  if ($key=='title' && empty($item)) {$item = "untitled";}
}
?>

answered Jan 7, 2011 at 21:25

Derek Downey

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2 Comments

webbiedave Over a year ago

Interesting but overhead makes this method many times slower than simple foreach.

Derek Downey Over a year ago

This could probably spark another question, but what overhead? or are you referring to the callback function?

Xavier Barbosa · Accepted Answer · 2011-01-07 22:48:10Z

0

If you want sweet and short, try this one

$result = array(
    array(
        'title' => 'foo',
        'body' => 'bar'
    ),
    array(
        'body' => 'baz'
    ),
    array(
        'body' => 'qux'
    ),
);

foreach($result as &$entry) if (empty($entry['title'])) {
    $entry['title'] = 'no val';
}

var_dump($records);

the empty() will do the job, see the doc http://www.php.net/manual/en/function.empty.php

answered Jan 7, 2011 at 22:48

Xavier Barbosa

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