Define an index on a new array in a loop?

Question

I have the following code:

$chart_data = array();
foreach ($range as $range_day) {
  foreach ($numbers as $number) {
    if($range_day == $number['date']){
      @$chart_data[$range_day] += $number['events'];
    } else {
      if(isset($chart_data[$range_day])){
        $chart_data[$range_day] += 0;
      }
    }
  }
}

This line: $chart_data[$range_day] += 0; was giving me an undefined index error, so I added the isset check, but it's not set so it wrecks my array. I know that it's not set, and I don't care, but I read all over that the @ solution is in poor taste. How can I remove the error the correct way?

Jeroen · Accepted Answer · 2012-05-25 21:30:46Z

1

You could just set it to zero at the beginning:

$chart_data = array();
foreach ($range as $range_day) {
  $chart_data[$range_day] = 0;
  foreach ($numbers as $number) {
    if($range_day == $number['date']){
      $chart_data[$range_day] += $number['events'];
    } else {
      if(isset($chart_data[$range_day])){
        $chart_data[$range_day] += 0;
      }
    }
  }
}

edited May 25, 2012 at 21:30

answered May 25, 2012 at 21:15

Jeroen

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1 Comment

user212218 Over a year ago

Would recommend also removing error suppression, since it is no longer "necessary" once you add the isset() check.

Pierre · Accepted Answer · 2012-05-25 21:24:56Z

1

Did you take a look at the array_key_exists function: http://php.net/manual/en/function.array-key-exists.php ?

Something like:

$chart_data = array();
foreach ($range as $range_day) {
  foreach ($numbers as $number) {
    if(!array_key_exists($range_day, $array)) {
      $chart_data[$range_day] = 0;
    }
    if($range_day == $number['date']){
      $chart_data[$range_day] += $number['events'];
    }
  }
}

edited May 25, 2012 at 21:24

answered May 25, 2012 at 21:15

Pierre

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1 Comment

user212218 Over a year ago

Would recommend also removing error suppression, since it's no longer "necessary" once you add the array_key_exists() check.

webbiedave · Accepted Answer · 2012-05-25 21:40:43Z

1

You can check if it's not set, then set it:

foreach ($numbers as $number) {
    if (!isset($chart_data[$range_day])) {
        $chart_data[$range_day] = 0;
    }
    if ($range_day == $number['date']) {
        $chart_data[$range_day] += $number['events'];
    } else {
        $chart_data[$range_day] += 0; // you're just adding 0 so why have this line at all?
    }
}

This answers assumes that there is the possibility that $range could contain a duplicate $range_day and so it won't overwrite the corresponding element in $chart_data.

edited May 25, 2012 at 21:40

answered May 25, 2012 at 21:17

webbiedave

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