How to check whether pattern is matched by using preg_replace only - php

Question

Currently, I have the following code, which use to perform pattern matching & pattern replacing.
<?php
function fun($text) {
if (preg_match("/^(ATE|EAT)\s+(\S+).*/", $text)) {
$text = preg_replace("/^(ATE|EAT)\s+(\S+).*/", "EAT $2", $text);
} else {
$text = preg_replace("/.*(ATE|EAT).*/", "EAT", $text);
}
return $text;
}
// EAT pizza
echo fun('EAT pizza') . "\n";
// EAT pizza
echo fun('EAT pizza at paris') . "\n";
// EAT
echo fun('I EAT pizza at paris') . "\n";
I feel the above code is not optimized, as I'm performing preg_match before preg_replace. I feel this is redundant.
I tried to check the returned string from preg_replace
<?php
function fun($text) {
$tmp = preg_replace("/^(ATE|EAT)\s+(\S+).*/", "EAT $2", $text);
// I don't think this is the correct way to check for "Not Match" ?!
if ($tmp === $text) {
$tmp = preg_replace("/.*(ATE|EAT).*/", "EAT", $text);
}
return $tmp;
}
// EAT pizza
echo fun('EAT pizza') . "\n";
// EAT pizza
echo fun('EAT pizza at paris') . "\n";
// EAT
echo fun('I EAT pizza at paris') . "\n";
However, fun('EAT pizza') will fail, as it will print out EAT instead of expected EAT pizza.
Is there a correct way to optimize the above code?

Answer 1

I assume all you actually ask for is to know how to know if there where any replacements in your preg_replace since it is quite unclear what you actually want to achieve.
From the PHP Documentation on preg-replace:
Description
mixed preg_replace ( mixed $pattern , mixed $replacement , mixed $subject [, int $limit = -1 [, int &$count ]] )
[..]
count
If specified, this variable will be filled with the number of replacements done.
So if you add a count to your preg_replace, you'll get the number of replacements, thus the number of occurances.
Example given (thou this is kind of into the blue due to lack of information):
function fun($text) {
$count = 0;
$tmp = preg_replace("/^(ATE|EAT)\s+(\S+).*/", "EAT $2", $text, -1, $count);
if ($count == 0) {
$tmp = preg_replace("/.*(ATE|EAT).*/", "EAT", $text);
}
return $tmp;
}
So this will replace ATE <something> or EAT <something> with EAT <something>, or, if neither of those where found, it will attempt to replace ATE or EAT with EAT.

Answer 2

Try with following function:
function fun($text) {
$tmp = str_replace('ATE', 'EAT', $text);
$pos = strpos($text, 'EAT');
if ($pos < 0) {
return $text;
} else if ($pos > 0) {
$tmp = preg_replace('/^.*?EAT/', 'EAT', $tmp);
}
$tmp = preg_replace("/^EAT\s+(\S+).*/", "EAT $2", $tmp);
return $tmp;
}