I agree, just use it because

Greg K — Sat, 30 Aug 2008 16:50:00 +0000

I agree, just use it because most of the time it works is bad practice.

You need to know the difference, and use it accordingly to the circumstance. I don't think their is a definite place to draw the line, it is up the programmer to have to ability to determine that when coding.

For example, If I have a div on a page to contain someones phone number if there was a phone number entered in a form, and I don't want the div to show if there wasn't one, I'm not going to check every possible thing about the variable.

$strPhoneNum = preg_replace("/[^0-9]/","",$_POST["txtPhoneNum"]);

if ($strPhoneNum != '') {
  echo "<div id='PhoneNum'>" . format_phone($strPhoneNum,'US') . "</div>\n";
}

(Note, I've tried editing this to display right, it still seems to be wrapping lines and changing fonts in the middle???)

In this case, i only care if there is at least a char. yes I could have use if(strlen($strPhoneNum)>0) but I prefer to not use a function if not needed.

-Greg

Greg K wrote: Usually for

greg — Sat, 30 Aug 2008 14:51:28 +0000

Greg K wrote:

Usually for most programming though, treating "" and NULL the same works well, but there are times where a difference is noticed and/or needed.

-Greg

Yes, and the difference is because, well, there is a difference. Where would you draw the line to differences and specific definitions of something?

"Well, I only need a rough estimate, and as I'm working with numbers in the millions 1 is the same as 2 in my circumstance."
Using "one or the other" because "most" circumstances allow it without a problem is bad coding imo. The differences should be understood and the correct one used in the correct circumstances.

$arc_cats = (array) null;

John_audson — Sat, 30 Aug 2008 10:30:46 +0000

$arc_cats = (array) null; try it.

Yes, but there are times

Greg K — Sat, 30 Aug 2008 03:08:45 +0000

Yes, but there are times when you do have a difference between a null value and an "empty" value

code at work had to figure out a "glitch", there was an enum field in sql, either an empty string or "checked"

well the items that were imported in when it began, didn't have that field, so they were all NULL. In SQL $field<>"checked" is NOT true if the field is actually NULL. took me a little bit to track that one down (edited the table to set the default value to be empty sting)

Also anohter issue brought up.. isset($arrayName['key'] and array_key_exists('key',$arrayName) will return different values if $arrayName['key'] is NULL (the isset will return FALSE)

Usually for most programming though, treating "" and NULL the same works well, but there are times where a difference is noticed and/or needed.

-Greg

That's what I thought, which

pr0gr4mm3r — Fri, 29 Aug 2008 22:02:18 +0000

That's what I thought, which is why I don't understand why it's being used this way.

Greg K is absolutely

decibel.places — Fri, 29 Aug 2008 21:19:16 +0000

Greg K is absolutely correct: $src_cats = (array) somevalue;

http://us.php.net/language.types.type-juggling

anyway, doesn't

$src_cats = array();

create an empty array?

and

$subcategories_content = "";

creates an empty string?

I could understand using

Greg K — Fri, 29 Aug 2008 18:55:34 +0000

I could understand using type casting to make it so if you check the variable type, even though it is null, it would pass as an array, however I would think it would be this:

$arc_cats = (array) null;

Either was, I don't think I would use it that way, a little to confusing.

-Greg