Undefined offset error in array index

Question

I have a while loop that runs if the index of an array is null. However, when I use the explode method it throws an undefined offset error for while ($temptext[1] == null). But, if I comment the explode line out, it no longer throws the undefined offset error. I'm confused about that part, because $temptext[1] is null whether it explodes or not. So why is one of them throwing an error, and the other one isn't? And lastly, how do I fix this, so I can use the while loop to compare the empty array index without it throwing an error?

$temptext = null;
$count = 1;
$text = ",";
$textX = "Hello there";

while ($temptext[1] == null && $count > 0) {

$count--;
$temptext = explode($text,$textX,2);

}

P.S: I'm running this snippet on PhpFiddle.org.

@DannyPhantom Yes. You're right. It works now. Can you explain why? The original code works fine on my web server. This only happens on PhpFiddle. And wow. I just got a down vote. — jessica
– jessica, Commented Aug 30, 2015 at 17:33

Blaž Zupančič · Accepted Answer · 2015-08-30 17:35:03Z

1

If you check for existance of an array element by using $array[1] == null , php will throw a Notice: Undefined offset: 1 , you should use !isset($array[1]) instead. Otherwise, your code contains no errors.

answered Aug 30, 2015 at 17:35

Blaž Zupančič

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3 Comments

jessica Over a year ago

How come that never happens on my web server?

Blaž Zupančič Over a year ago

Probably because it has PHP notices turned off.

Blaž Zupančič Over a year ago

Again, your code was never throwing an error and was working correctly, it was just noticing, that the array element you were trying to access doesn't exist. PHP doesn't know that you intend to check for existance when using $var == null , that's why !isset($var) is there.

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