How to insert character inside a word while keeping the case - php

Question

I want to insert a character inside a word in a string if a word match is found while keeping the case. This code works fine but I have to specify the resulting word.
$string = "Quick brown fOx jumps right over the lazy dog.";
$swears = array(
"BROWN" => "BRO.WN",
"fox" => "f.ox",
"Dog" => "D.og",
);
$filtered = str_ireplace(array_keys($swears), array_values($swears), $string);
The problem with this code is any "brown" becomes BRO.WN
Is it possible to insert a character if the word matches. Like Brown becomes Bro.wn; brown becomes bro.wn while keeping the case.

Answer 1

There are probably much better ways to do that, but here is the only answer I came up with :
foreach($swears as $swear => $modified_swear) {
$swear_pos = stripos($string, $swear);
if($swear_pos !== false) {
$swear_len = strlen($swear);
if($swear_len >= 3) {
$new_string = substr($string, 0, $swear_pos);
$new_string .= substr($string, $swear_pos, $swear_len-2);
$new_string .= '.';
$new_string .= substr($string, $swear_pos+($swear_len-2));
$string = $new_string;
}
}
}
This code works only if you actually was trying to add a single dot before the two last characters of a swear.
EDIT :
New code that can modify all occurences of a list of words.
$searched_pattern = '/\b(?:';
foreach($swears as $swear => $modified_swear) {
$searched_pattern .= '('.$swear.')|';
}
$searched_pattern = rtrim($searched_pattern, '|');
$searched_pattern .= ')\b/i';
$string = preg_replace_callback(
$searched_pattern,
function($matches) {
$word = $matches[0];
$swear_len = strlen($word);
if($swear_len >= 3) {
$new_word .= substr($word, 0, $swear_len-2);
$new_word .= '.';
$new_word .= substr($word, $swear_len-2);
$word = $new_word;
}
return $word;
},
$string
);

Answer 2

I'm not exactly clear what you want?
There are alternatives for this test. Then do a str_replace inserting a char into a specific position.
<?php
$string = "Quick brown fOx jumps right over the lazy dog.";
$swears = array(
"BROWN" => "BRO.WN",
"fox" => "f.ox",
"Dog" => "D.og"
);
$string_arr = explode(" ",$string);
$swears_arr = array_keys($swears);
foreach ($swears as $swear_key => $swear_word) {
foreach ($string_arr as $key => $word) {
if (preg_replace('/[^a-z]+/i', '', strtolower($word)) == strtolower($swear_key)) {
$string_arr[$key] = substr_replace($word, '.', 1, 0);
}
}
}
// put the sentence back together:
$new_string = implode(" ",$string_arr);
print_r($new_string);
?>