php - Check for duplicate in array -

i have created html form passes data text file , text file saves data on array.

i cannot figure out how go checking see if value exists before putting input in array or text file.

     name: <input type="text" name="name" /><br />     email: <input type="text" name="email" /><br />     <input type="submit" name="save" value="submit" /><br />     <?php $myarray = array();  if (isset($_post['save'])) { /*the file created in same directory php code resides *a+ not overwrite text*/ $myfile = fopen("donorlist.txt", "a+") or die("unable open file!"); //get data entered user form fwrite($myfile, $_post['name']); fwrite($myfile, " "); fwrite($myfile, $_post['email']); fwrite($myfile, "\r\n"); //next line fclose($myfile);//close file  textoutput();//call function }  print_r($myarray); //creating function make code more readable  function textoutput() {     $lines = file('donorlist.txt');     foreach ($lines $lines_num => $line)     {         echo "user input: ".htmlspecialchars($line)."<br />\n";     }      $file = fopen("donorlist.txt", "r");     while(!feof($file))     {         $myarray[]= fgets($file);        }     fclose($file);   }  ?> 

you may try after fullfilling array

$myarray = array_unique($myarray); 

also can check if value in array before pushing it:

while(!feof($file)) {     $line = fgets($file);     if (!in_array($line, $myarray)) {         $myarray[]= $line;     }    } 

here have info complexity: add array if isn't there already