Question

Im using this code to read out of a file, Im getting an error Warning on in_array() for Wrong datatype for second argument.

if (isset($_POST['submit'])) {
  $SongToAdd = stripslashes($_POST['SongName']) . "\n";
  $ExistingSongs = array();

  if (file_exists("SongOrganizer/songs.txt") && filesize("SongOrganizer/songs.txt") > 0) {
    $ExistingSongs = file("SongOrganizer/songs.txt");
  }
}

if (in_array($SongToAdd, $ExistingSongs)) {
  echo "<p>The song you entered already exists!<br />\n";
  echo "Your song was not added to the list.</p>";

The text file contains:

Bang Bang
Doctor
Hello
Ice Cream Man
Show Me
Doctor

Answer 1

Well, what about the first time your page loads? If $_POST['submit'] is not set then $ExistingSongs will be null. in_array is right to complain about that.

If you were developing with all errors enabled — done with error_reporting(E_ALL | E_STRICT) or through php.ini — then you ‘d also have gotten a notice about $ExistingSongs being an undefined variable.