Need some help

[Fmdpa]

I am reading a book (Learning PHP 5), and there are a couple things on which I am getting hung up. 1. Are "echo" and "print" redundant? Are they from different PHP eras, and one is not recommended anymore?2. Same type of problem with "include" and "require"...?3. If $_POST is a variable, would $_BANANA do the same thing? In the cases I've seen $_POST used, I can't ever find $_POST's value being set. Is it a different kind of variable?My biggest problem is with understanding the printf() function. Here's an example from the book.

$price = 5; $tax = 0.075printf('The dish costs $%.2f', $price * (1+$tax));

It does give an explanation, but I just not getting it. Another example:

$zip='6520';$month=2;$day=6;$year=2007;printf("ZIP is %05d and the date is %02d/%02d/%d", $zip, $month, $day, $year);

It looks like the format rules are filled respectively with the listed variables and/or operations. I understand the padding characters and that the % sign is mandatory, but what do the "5d", "2d" and "2f" mean?

[thescientist]

you should go over to php.net and search over there, you should be able to find everything you need there.$_POST and $_GET refer to the way information can be passed between pages. You can look that up here on w3schools too.

[Fmdpa]

I understand what $_POST and $_GET are. In one, (post) the info is passed invisibly through the HTTP header, but in the other (get) the info is transferred via the URL. But in learning PHP, I learned that anything that begins with a $ sign is a variable. That's where I am confused.

[thescientist]

what are you confused about? POST and GET are global variables. but you are also right in that you indicate a variable to be used in a script by putting a $ before it.

[Fmdpa]

I had never learned about predefined variables I just took a peek at the PHP manual, and it cleared that issue up. Why I was confused is because I thought all variables had to be assigned a value by the code writer.

[thescientist]

not necessarily, although it is good habit to at least define them and some would argue to initialize them. I prefer both.

[justsomeguy]

Are "echo" and "print" redundant?

More or less.

one is not recommended anymore?

They'll both be around for a while.

Same type of problem with "include" and "require"

Include and require behave differently when the file is not found.

If $_POST is a variable, would $_BANANA do the same thing?

What? $_POST doesn't "do" anything, it's a container for data.

In the cases I've seen $_POST used, I can't ever find $_POST's value being set.

The values that go inside $_POST, $_GET, $_COOKIE, $_SERVER, etc are all set by PHP. You can set them yourself also though, e.g.:$_POST['xxx'] = 'hi';

It does give an explanation, but I just not getting it.

This should explain the format string:http://www.php.net/manual/en/function.sprintf.php

[Fmdpa]

Thanks! That helps a lot.

[Synook]

Note that echo and print return different values (nothing and 1 respectively).

[Fmdpa]

Could you please clarify? Is that if the value for echo and print is nothing?

[Synook]

No - it's their return value. They return the same thing no matter what parameters you put it. Consider:

<?php	$a = print "print"; //prints "print"	echo $a; //prints "1"	$b = echo $a; //error?>

Did you have a look at their manual pages?

[23.12.2012]

Note that echo and print return different values (nothing and 1 respectively).

I think this is because echo is a language construct, just like include and require, while print is a funciton.

[Synook]

Print is actually a construct as well, but it is unusual in that it returns a value.

print() is not actually a real function (it is a language construct) so you are not required to use parentheses with its argument list.