CODEWITHSUNDEEP
php
skolind
skolind

Reputation: 1754

PHP - Workaround undefined index for array

I'm trying to simply add +1 to an array like this

$game['teamA']['goals']++;

But then it'll throw me an error about undefined index. And I guess that's because $game['teamA']['goals'] is not set before I am adding a value to it.

But isn't there a way to workaround this?

I could set the $game['teamA']['goals'] = 0 in start of simulation, but then I have to do that with freekicks, penalties, cards etc., AND do it for both teams. Isn't there another way of doing this?

Thanks in advance :)

Upvotes: 0

Views: 95

Answers (4)

Rudolf Mühlbauer
Rudolf Mühlbauer

Reputation: 2531

write a wrapper function to set the values.

<?php

function increment(&$dict, $key1, $key2) {
  if (!isset($dict, $key1))
    $dict[$key1] = array();
  if (!isset($dict[$key1], $key2))
    $dict[$key1][$key2] = 1;
  else
    $dict[$key1][$key2] ++;
}

$game= array();
increment($game, "teamA", "goals");
var_dump( $game);
?>

It really depends on what you expect on the runtime; if these operations are called often, it would be better to create all array indices before doing anything else, like https://stackoverflow.com/a/12873359/1689451 suggested.

Upvotes: 1

Havelock
Havelock

Reputation: 6968

I'd suggest you go with a "proper initialisation", as you suggested. That would some code to your program but it's always better then on each update to check. Better do 

$game = array( 'teamA' => array('goals'       => 0,
                                'freekicks'   => 0,
                                'penalties'   => 0,
                                // etc ...                       
                          ),
               'teamB' => array('goals'       => 0,
                                'freekicks'   => 0,
                                'penalties'   => 0,
                                // etc ...
                          )
        );

instead of 

if(isset($game['teamA']['goals']))
    $game['teamA']['goals']++;
else
    $game[teamA]['goals'] = 1;

There's nothing wrong to properly init your variables - all of them. It's even advisable to do so.

Upvotes: 2

Luke Mills
Luke Mills

Reputation: 1606

You should ALWAYS initialise variables before they are used. One way to do this would be:

$game = array('teamA' => 
                  array(
                      'goals' => 0,
                      'freekicks' => 0,
                      'penalties' => 0,
                      ....
                  ),
              'teamB' =>
                  array(
                      'goals' => 0,
                      'freekicks' => 0,
                      'penalties' => 0,
                      ...
                  )
              );

Upvotes: 2

Praveen Kumar Purushothaman
Praveen Kumar Purushothaman

Reputation: 167182

You can do one thing. Before incrementing, check for existence of the array, if not, create one! As simple as that. You can use a built-in function called isset(), which checks the existence of the variable.

Short Way:

(isset($game['teamA']['goals']) ? $game['teamA']['goals']++ : $game['teamA']['goals'] = 1;

Or using if condition:

if (isset($game['teamA']['goals'])
    $game['teamA']['goals']++;
else
    $game['teamA']['goals'] = 1;

Upvotes: 0

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