How to put the a string into a text file in PHP?

Question

How do I put a string into a txt file in php?

I want to write string like this:

        1,hello,world!
        2,welcome

Then have

Answer 1

To write to a txt file:

<?php
$file = 'file.txt';
$data = 'this is your string to write';
file_put_contents($file, $data);
?>

To echo contents of that file somewhere on a page (remember the page must have a .php extension for php to work):

<?php
// place this piece of code wherever you want the file contents to appear
readfile('file.txt');
?>

EDIT:

To answer your another question from the comments:

When saving your data to the file, the original code is OK, just use that. The different code comes when echoing the contents from the file, so now it will look like this:

<?php
$contents = file_get_contents('file.txt');
$contents = explode("\n", $contents);
foreach($contents as $line){
   $firstComma = (strpos($line, ","))+1;
   $newLine = substr($line, $firstComma);
   echo $newLine."\n"; 
}
?>

Try it like that. I don't have my server here, so I cannot test it, but I believe I didn't make any mistake there.

Answer 2

You can write a string to a file with file_put_contents. Not sure what you mean by output to HTML.
Do you just want echo?