PHP array check for existing index

Question

Not very strong in PHP so here is my question:

I am building a simple array to return as json, populating it with data from another array. The $eventarray may have the index gas or may not so I need to check for existing gas index and if it exist get the value if not populate with a default value.

How would I do that the most optimal way?

Again not that strong in PHP.

Here is the array:

 $somearr = array(
       "actiontaken"=>sprintf("%s", $eventarray['desc']),
        "actionname" =>sprintf("%s", $eventarray['name']),
        "type" =>sprintf("%s", $eventarray['type']),
        "subtype" =>sprintf("%s", $eventarray['name']),
        "min" =>sprintf("%s", $eventarray['min']),
        "gas" =>sprintf("%s", $eventarray['gas']),
        "playerId"=>$value['p'],
        "name" =>$value2['name'],
        "race" =>$value2['race']
);

Fyi, you do not need the sprintf calls. Just use the variables directly! — ThiefMaster
– ThiefMaster, Commented May 20, 2012 at 23:54

ThiefMaster · Accepted Answer · 2012-05-20 23:53:55Z

4

You can use isset() to check if the element exists (and is not null):

isset($eventarray['gas']) ? $eventarray['gas'] : 'defaultvalue'

Note: In case null is a possible value where you do not want the default value to be used you cannot use isset but have to use array_key_exists($eventarray, 'gas') instead.

edited May 20, 2012 at 23:53

answered May 20, 2012 at 23:51

ThiefMaster

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4 Comments

Samy Arous Over a year ago

php doc recommand using array_key_exists instead. I also used to use isset but it seems it return false result on some case (if the key is null?!!).

ThiefMaster Over a year ago

Yes, as I mentioned: If the value is NULL it will return false. If that's not a problem for him, isset() is fine.

Vasile Laur Over a year ago

Thanks wasn't sure about the syntax in php, it very similar to C# syntax which I use all the time, and yes returning false on null is fine.

Okonomiyaki3000 Over a year ago

isset is supposedly quite a bit faster than array_key_exists (although it probably doesn't matter much) and it also has the ability to check several items at once. You can pass in any number of variables and it will only return true if they are all set. That can come in handy sometimes.

Menztrual · Accepted Answer · 2012-05-20 23:52:32Z

1

You could use a ternary operator to check for its existence, and set a default value.

The way it works is: ( condition ) ? [if true] : [ if false]

...
"gas" => (isset($eventarray['gas'])) ? $eventarray['gas'] : 'default',

answered May 20, 2012 at 23:52

Menztrual

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Comments

Samy Arous · Accepted Answer · 2012-05-20 23:52:11Z

0

use this

array_key_exists('gas', $somearr);

http://www.php.net/manual/en/function.array-key-exists.php

answered May 20, 2012 at 23:52

Samy Arous

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Comments

Sp4cecat · Accepted Answer · 2012-05-20 23:53:30Z

0

Initialise your $somearr array first with default values:

$somearr = array(
  'actiontaken' => 'default action',
  'actionname' => 'default action name',
  etc.. );

Then loop through $eventarray:

foreach( $eventarray as $event => $eventval ) {
  $somearr[$event] = $eventval;
}

answered May 20, 2012 at 23:53

Sp4cecat

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1 Comment

Okonomiyaki3000 Over a year ago

This is a good solution in many cases but I'd recommend using array_merge instead of the loop. $output = array_merge($default_values, $input);

Yefb · Accepted Answer · 2012-05-20 23:57:36Z

0

Use ternary operator:

"actiontaken"=>sprintf("%s", (isset($eventarray['desc']) && !empty($eventarray['desc'])) ?$eventarray['desc'] : 'Default Value'),

answered May 20, 2012 at 23:57

Yefb

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