PHP3 & PHP4 Differences?

oberon-ken-obi · 03-29-2005, 03:03 AM

Hi all

I'll be as succinct as possible.

I have a PHP3 book called "Professional PHP Programming" by Wrox Publishing www.wrox.com . Seems to be very extensive and cost me a packet so I am loath to just stop using it.

Now I am aware of a few differences ie in PHP4 you need to call form variables with $_REQUEST["variable"] or $_POST etc instead of just $variable in PHP3.
This seemed straight forward enough, so I just got on with it and did more examples. The fact I had to change these things seemed to grant a greater understanding so it was all good.

Now the further I go I find many more inconsistancies, ie no boolean variable type in php3 but php4 seems (in my limited understanding) to be recognizing them, at least the isset() function as the example uses (taken directly from the book) does not work correctly.

Code:

<?php  
$avail = isset($avail);     // Convert to Bool 
 echo ($_POST["avail"]); // Prints 1 if checked 
                                       // Prints 0 if unchecked 
?>

This prints "on" and not "1" if check box is selected but fails if not checked.

Escaping certain characters seems different as well. I could make a few more examples but you get the drift im sure.

Directives in php conf file are default for security/speed as suggested by php readme.txt.

I guess what I'm asking is will it be worthwhile to continue as I am, or will I just confuse myself further? Especially anyone who has used this particular book who migrated from ver3 to ver4.

Any suggestions for a ver4 book (if that is what is suggested) would be appreciated as well. Assume I am a novice for the purposes of book selection.
I have seen a book called Sams teach yourself PHP4 in 24 Hours. Seems to good to be true, thoughts on this book please.

Regards
Allan

clausi · 03-29-2005, 04:53 PM

I'd say, wait a while to get a proper PHP5 book because there have been several changes that make it worthwhile (the new OOP stuff, for example). Or just use this amazing tutorial, ehm, online book.

The PHP manual explains PHP3 to PHP4 changes. In general, the manual is really great resource.

oberon-ken-obi · 03-29-2005, 05:19 PM

Hey clausi

Thanks for the answer, it is almost exactly what I was asking :+)
Changes link was very helpful too.
Now, if I wait for the PHP5 books will I need to use PHP5 engine as well?
Untill then I will look into the amazing tutorial.
But for now its...
Hi Ho, Hi Ho, its off to work we go.

Regards
Allan

clausi · 04-01-2005, 01:12 PM

Quote:

Originally posted by oberon-ken-obi
Now, if I wait for the PHP5 books will I need to use PHP5 engine as well?

Uhm, sorry for the late answer.

I guess you will want to use it after figuring out all the additional functionality of PHP5 (basically better XML support, and much better and faster OOP support).

But to answer your question: Yes, of course you will need it -- at least, if you gonna use the new functions. However, PHP4 code is said to run fine on PHP5.

Unfortunatly, I don't know if the new version is available for your distro; neither Debian nor Ubuntu have packages yet. And finding a shared server with PHP5 is still tricky, also.

So, you better wait until PHP 5.1.* is out before you spend money on a book - I believe, adoption rate will increase when this happens. As I said, the manual should be sufficient meanwhile. And there are lots of interesting tutorials on the web. Just use google.