PHP: improving the loop that uses foreach? - php

Question

I use foreach to loop the array below and then making the order number to be store in the database,
$items_variable = array(
'page_id',
'page_content_1',
'page_content_2',
'page_content_3',
'page_content_4',
...
);
The code only loop 4 items from the array above (but what if I have these page_content_# increased in the future?)
foreach( $items_variable as $item_variable )
{
if (in_array($item_variable, array(
'page_content_1',
'page_content_2',
'page_content_3',
'page_content_4'
)))
{
if($item_variable == 'page_content_1') $order_in_page = 1;
if($item_variable == 'page_content_2') $order_in_page = 2;
if($item_variable == 'page_content_3') $order_in_page = 3;
if($item_variable == 'page_content_4') $order_in_page = 4;
....
}
}
The current method I have above doesn't look good to me especially when it comes to the line like this,
if($item_variable == 'page_content_1') $order_in_page = 1;
I will add more lines like this when I have page_content_# increased in the future and the script will look pretty ugly I suppose.
What if I have another type of data with order number (for instance - code_1, code_2, etc)? Then I have copy the code above and change the item name each time - this looks pretty gloomy isn't!
How can I make it better and dynamic?

Answer 1

Associative array
You can do this:
$items_definitions = array(
'page_content_1' => 1,
'page_content_2' => 2,
'page_content_3' => 3,
'page_content_4' => 4,
'page_content_5' => 5,
);
foreach( $items_variable as $item_variable ){
if( isset( $items_definitions[ $item_variable])){
$order_in_page = $items_definitions[ $item_variable];
}
...
}
Dynamically extracting last part of string
Or do it completely dynamically assuming that it's always page_content_{$order_in_page}, either with regexp as hackartist suggested or use "oldschool method":
$prefix = 'page_content_';
foreach( $items_variable as $item_variable ){
if( strncmp( $item_variable, $pregix, strlen( $prefix))){
continue; // Assume that you don't want to do anything if it doesn't match
}
$page = intval( substr( $item_variable, strlen( $prefix)));
if( !$page){
continue;
}
$order_in_page = $page;
}
I recommend studying examples from intval() documentation :)
Switch statement
Php provides switch which allows you to handle many different cases with relatively small amount of code.
foreach( $items_variable as $item_variable ){
switch( $item_variable){
case 'page_content_1':
$order_in_page = 1;
break;
case 'page_content_2':
$order_in_page = 2;
break;
case 'page_content_3':
$order_in_page = 3;
break;
...
default:
}
}
I'd however do this only if first two options wouldn't work out for you (eg. you need to call different function for each case).

Answer 2

not sure exactly what you want but try this instead of the if statement:
preg_match('/page_content_([0-9]+)/',$item_variable,$matches);
$order_in_page = $matches[1];

Answer 3

I'm not sure I understand your question, but maybe an associative array would be a solution for you. You can use it to match a string to a value:
$order_in_page = array(
'page_content_1' => 1,
'page_content_2' => 2,
'page_content_3' => 3,
'page_content_4' => 4,
'someotherpage' => 5,
'yet_another_page' => 6
);
$o = $order_in_page[$item_variable];
Stuff on the data structure
http://en.wikipedia.org/wiki/Associative_array
PHP Documentation
http://php.net/manual/de/language.types.array.php

Answer 4

Your current array, if you write it out with the explicit keys, looks like the following:
$items_variable = array(
0 => 'page_id',
1 => 'page_content_1',
2 => 'page_content_2',
3 => 'page_content_3',
4 => 'page_content_4',
...
);
Notice that the key number matches completely with the page content number. Thus, you could change the foreach loop to the following:
foreach( $items_variable as $order_in_page => $item_variable )
Now $order_in_page should be stored with the key number, which in your array correlates directly to the page content number. You may need to cast it into an int, although I am not sure of this fact:
$order_in_page = (int) $order_in_page;
If instead, your array looked like the following (without the 'page_id' element):
$items_variable = array(
0 => 'page_content_1',
1 => 'page_content_2',
2 => 'page_content_3',
3 => 'page_content_4',
...
);
Do the same thing as above, but add one to the result:
++$order_in_page;
If casting is needed, cast before the increment.

Answer 5

foreach($items_variable as $item_variable) {
preg_match('/[0-9]*$/',$item_variable , $suffix);
$suffix = $suffix[0];
if ($suffix !== '') {
# code 1
} else {
# code 2
}
}

Answer 6

I'm not sure I understood your question, but you might want to store your data in a multidimensional array, like:
$items_variable = array(
'page_id',
'content' => array(
//content
)
);
Then you could just iterate through each content-array, such as:
foreach($items_variable['content'] as $content) {
//do stuff with the content
}
No need for regex or other stuff.