搜索文件中的元素数组，并将其替换为另一个元素数组-php

Question

I am trying to

1. open and read a file,
2. Search a few words within the file,
3. Replace these words with some other words,
4. Put content into the file again.

The words for search and replace are taken dynamically from user input boxes. Here's the code I am going with,

$filename = 'test1.txt'; 
($handle = fopen($filename, 'r+')) or die(); 
$content = fread($handle, filesize($filename));
echo $content.'<br>'.'<br>';

if (isset($_POST['findtext']) && isset($_POST['replacetext'])) {
$findtext = $_POST['findtext'];
$replacetext = $_POST['replacetext'];
if (!empty($findtext) && !empty('$replacetext')) {
    $ftxtarray = explode( ',', strtolower($findtext));
    $rtxtarray = explode(',', strtolower($replacetext));
    //  code?
    echo $content;
    } else {
    echo 'Please type in "Replace:" words and "Replace with:" words..';
    }

}

And the HTML,

<form action="firstfile.php" method="POST">
<br>Replace:<br>
<input type="text" name="findtext"><br>
Replace with:<br>
<input type="text" name="replacetext"><br>
<input type="submit" value="Submit">

Lets say "test1.txt" contains few words including "John Doe" and user types in "John,Doe" in the "Replace:" field and "Richard,Roe" in the "Replace with:" field. Which method should I use to replace the specified words?

Answer 1

Use str_replace() and put in first parameter array of words to find, in second parameter array with the exact length as the first one, in third contents of a file loaded into variable, and you're good to go.