How to remove partial line repeats in php?

Question

PHP

Good day.
There are files with lines like:
album-58860049 _210149013
album-58860049 _210149014
album-58860049 _210149015
album-13123339_210143131
As you can see, the first 3 lines have a non-unique album indicator (its length can be different.)
How to leave only 1 option?
To get a list after processing, let's say this:
album-58860049 _210149015
album-13123339_210143131

Answer 1

A banal option:
- open a file for reading,
- create a new file for writing,
- create an empty array.
- for each line read:
- select an album from it,
- if such an entry is not yet in the array:
---- add it to the array,
---- write the line to the output file.
If the output file is not needed, instead we work with an array in memory, the logic is the same.

Answer 2

Thank you all, here's the script, that's who will come in handy.

<?php
$input = file('album.txt');
$data = array();
foreach ($input as $value) {
$str = substr($value, 0, strpos($value, '_'));
if (in_array($str, $data)) {
} else {
$data[] = $value;
echo $value."
";
}
$data[] = $str;
}
?>

Answer 3

$albums = explode("\r\n", file_get_contents( 'file.txt') );
$result = [];
foreach($albums as $item){
  $frag = explode('_', $item, 2);
  $result[ $frag[0] ] = $frag[1];
}
$newstr = "";
foreach($result as $key => $val ){
  $newstr .= $key .'_'. $val . "\r\n";
}
file_put_contents( 'newfile.txt', $newstr);