Algorithm to find and replace price within text - php

Question

i have an aribitrary piece of text, that is supplied through magento within the CMS,
the text that is retrieved may have a price within it. So for example
Delivery text
Orders over €200 are delivered Free Of Charge. €10 charge for orders
under €200. There may be additional charges for heavy goods.
How would i go about replacing each occurance of a price, so in the case above i would change
€200
€10
€200
I want to replace these prices based on the current currency being used.
$fromCur = 'EUR'; // currency code to convert from
$toCur = 'USD'; // currency code to convert to
$toCurrencyPrice = Mage::helper('directory')->currencyConvert($fromCurrencyPrice, $fromCur, $toCur);
This is how i will convert the prices, the only thing is , i do not know how i will find the prices within the text
Here is what i have tried so far
//the text to search
$text = 'Orders over €200 are delivered Free Of Charge. €10 charge for orders under €200. There may be additional charges for heavy goods.';
$matches = array();
//find a price with a euro symbol
preg_match_all("/€[0-9]+/", $text, $matches);
$ints = array();
$counter = 0;
//remove the euro symbol
foreach ($matches[0] as $match) {
//echo substr( $match,6) . '<br/>';
$ints[$counter] = substr( $match,6);
$counter++;
}
//now i know i have to convert it to my price, but my issue is, how do i now replace new values, with the old values inside the $ text varaible
Lets say i wants to change the matches found , with the elements in $ints (the price without the euro symbol). How would i do this?

Answer 1

Not entire solution, but to begin, you can extract prices and unit using :
$text = "I bought a shoes 33 $, a tee shirt 44 $ and a short 55 €.";
$match = array();
preg_match_all("/([0-9]+)[ ]*(€)|([0-9]+)[ ]*([$])/", $text, $match);
print_r($match);
It will give you:
Array
(
[0] => Array
(
[0] => 33 $
[1] => 44 $
[2] => 55 €
)
[1] => Array
(
[0] =>
[1] =>
[2] => 55
)
[2] => Array
(
[0] =>
[1] =>
[2] => €
)
[3] => Array
(
[0] => 33
[1] => 44
[2] =>
)
[4] => Array
(
[0] => $
[1] => $
[2] =>
)
)
And you will able to decide what logic you want to apply (knowing values, and money sign)

Answer 2

The PHP documentation is a good place to start. You have to use string search functions. Try figuring out yourself, you have the whole PHP documentation to look in. Just search string search php on google and you will find loads of informations.
Here are some functions that might help you :
http://php.net/manual/en/function.strpos.php
http://php.net/manual/en/function.preg-match.php
I think pregmatch will suit your needs. Understand that function and use it in your scope.
Good luck !

Answer 3

Assuming you always have € as your incoming currency, try next code:
$string = 'Orders over €200 are delivered Free Of Charge. €10 charge for orders under €200. There may be additional charges for heavy goods.';
$pattern = "#€[0-9]{1,}#";
$newStr = preg_replace_callback($pattern, create_function(
'$matches',
'return Mage::helper(\'directory\')->currencyConvert($matches[0], \'EUR\', \'USD\');'
), $string);
echo $newStr;
I haven't tested it, but it should work;
UPDATE:
I just thought about convert you have, and you probably need to remove and then add the currency symbol first; but you should have a starting point for that - just play with return function