Programming Forums > Web Development and Design > PHP

jstephens · Oct 27th, 2005, 11:06 PM

I am new to PHP and in need of some help. My questions are :

1) How often will I use arrays ?
2)When are good times for using Functions ?

I am using O'Reilly's Learning PHP 5 and currently on functions but I am still confused as you can see. Any help would be appreciated.

crazykid48x · Oct 28th, 2005, 12:20 AM

I know! you'll use arrays often in not only php but in almost all other languages as well. And the best time to use functions is when you have a chunk of code that you repeat several times.

edit: oh yeah, functions are also useful when you want your code to be broken into smaller independant peices. (thats a good habit by the way)

Lich · Oct 28th, 2005, 8:35 AM

My rule of thumb is make a function for any piece of code that you may use more than once.

DaWei · Oct 28th, 2005, 9:13 AM

PHP has a propensity to produce a LOT of its data in arrays. There are alternatives (objects, for instance), but arrays are extremely common. After all, that's what a row in a database table essentially IS: an associative array.

A clue to why you might want to write a function lies it it's name: function. Perhaps you never thought of it like that. Connecting to a database is a function. Emitting an HTML table of a certain structure, over and over, is a function. Why mix the two? They're not related. Scrambled eggs are for breakfast, not applications.

jstephens · Oct 28th, 2005, 3:23 PM

So can you place your functions into a seperate page and use an include? All the examples in the book show poor usage of them. I am looking for an actual real world Example of how and when to use them. One of the examples in the book is as follows:

function page_Header($color) {
print "<html><head><title>Welcome to My Site </title></head>";
print "<body bgcolor = " . ' $color ' . ">";
}

This is typed into the same web page as the call to the function. So how would I use this over again.

tempest · Oct 28th, 2005, 4:18 PM

Use [ P H P ] [ / P H P ] tags around PHP code in the future, please...

That's a VERY bad example of functions, since it'll only be called once (and could be simplified).

[php]
<?php
function multiply($n1, $n2) {
return $n1 * $n2;
}

echo "9 * 9 = " . multiply(9, 9) . "<br>\r\n";
?>
[/php]

Mocker · Oct 29th, 2005, 11:07 PM

Quote:

Originally Posted by jstephens

So can you place your functions into a seperate page and use an include? All the examples in the book show poor usage of them. I am looking for an actual real world Example of how and when to use them. One of the examples in the book is as follows:

function page_Header($color) {
print "<html><head><title>Welcome to My Site </title></head>";
print "<body bgcolor = " . ' $color ' . ">";
}

This is typed into the same web page as the call to the function. So how would I use this over again.

It might be simplified, but say you make one php program to serve up lots of websites (ie index.php?page=home index.php?page=gallery index.php?page=login)

You are going to be duplicating a lot of html output, so you would want all the html that is going to be the same in every page to be in its own function, or set of functions. So everytime you make a webpage you can call

page_Header();
if($_GET['page']){
//decide what content to show based upon the page
}
page_Footer();

this is really basic, but the point is there is a reason the header was put in its own function. You want to keep the different parts of your program defined.

Oct 27th, 2005, 11:06 PM	#1
jstephens Newbie Join Date: Oct 2005 Posts: 12 Rep Power: 0	Array and Function Help. I am new to PHP and in need of some help. My questions are : 1) How often will I use arrays ? 2)When are good times for using Functions ? I am using O'Reilly's Learning PHP 5 and currently on functions but I am still confused as you can see. Any help would be appreciated.

Oct 28th, 2005, 12:20 AM	#2
crazykid48x Programmer Join Date: Apr 2005 Posts: 96 Rep Power: 4	I know! you'll use arrays often in not only php but in almost all other languages as well. And the best time to use functions is when you have a chunk of code that you repeat several times. edit: oh yeah, functions are also useful when you want your code to be broken into smaller independant peices. (thats a good habit by the way) __________________ I had my portable CD player, and took it in the bathroom with me while I went to pee. And the second I whipped my penis out, the theme song to 'Rocky' started playing. I've never felt more manly than in that moment.

Oct 28th, 2005, 8:35 AM	#3
Lich Professional Programmer Join Date: May 2005 Location: Detroit Posts: 254 Rep Power: 4	My rule of thumb is make a function for any piece of code that you may use more than once. __________________ --John Cruz Web Developer www.cruzweb.net

Oct 28th, 2005, 9:13 AM	#4
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	PHP has a propensity to produce a LOT of its data in arrays. There are alternatives (objects, for instance), but arrays are extremely common. After all, that's what a row in a database table essentially IS: an associative array. A clue to why you might want to write a function lies it it's name: function. Perhaps you never thought of it like that. Connecting to a database is a function. Emitting an HTML table of a certain structure, over and over, is a function. Why mix the two? They're not related. Scrambled eggs are for breakfast, not applications. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Oct 28th, 2005, 4:18 PM	#6
tempest Programming Guru Join Date: Oct 2004 Posts: 1,041 Rep Power: 5	Use [ P H P ] [ / P H P ] tags around PHP code in the future, please... That's a VERY bad example of functions, since it'll only be called once (and could be simplified). [php] <?php function multiply($n1, $n2) { return $n1 * $n2; } echo "9 * 9 = " . multiply(9, 9) . "<br>\r\n"; ?> [/php] __________________

Oct 28th, 2005, 3:23 PM	#5
jstephens Newbie Join Date: Oct 2005 Posts: 12 Rep Power: 0	So can you place your functions into a seperate page and use an include? All the examples in the book show poor usage of them. I am looking for an actual real world Example of how and when to use them. One of the examples in the book is as follows: function page_Header($color) { print "<html><head><title>Welcome to My Site </title></head>"; print "<body bgcolor = " . ' $color ' . ">"; } This is typed into the same web page as the call to the function. So how would I use this over again.

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Programming Forums > Web Development and Design > PHP

Array and Function Help.