Deleting/excluding empty lines from being saved and used in PHP - php

Question

I'm currently fighting with excluding empty lines to be saved into the array $presidents (and by doing that, solving a problem where the foreach loop echoes the strings without Names).
I've tried a few things which should have worked, in my amateur opinion of course (preg_match(), trim(), etc.).
Can someone help me with this?
$file = fopen("namen2.txt", "r");
$presidents = array();
$count = count(file("namen2.txt"));
for($i = 1; $i <= $count;){
$file_line = fgets($file);
$line = explode(" ", $file_line);
$president = array();
$president["firstname"] = $line[0];
if(empty($president["firstname"] == false)){
$president["lastname"] = $line[1];
$president["counter"] = $i;
$presidents[] = $president;
$i++;
}
else{echo "fehler";}
}
foreach($presidents as $president_order){
echo "Hey ". $president_order["firstname"]. " ". $president_order["lastname"]. ", du bist der ". $president_order["counter"]. ". Präsident der USA in meiner Liste. \n";
}
Edit: I've solved my problems by changing conditions and controlling my input at the insertion phase, thanks for the great tips!

Answer 1

You should be dealing with spaces and unwanted characters at the insertion phase of the data, not after it so you should go back to that code and clean the data before the insertion takes place.
Using PHP's trim should work, there's no reason why it should not work for you. If you have a variable holding a string like " Firstname Lastname " then using that function will turn it to "Firstname Lastname".
It seems you are splitting each piece of data with spaces... that's not a good idea considering your data may possibly have to include spaces (First names can have spaces too, Mary Jane for example).

Answer 2

You can spot and delete empty lines with the following regular expression:
preg_replace("/(^[\r\n]*|[\r\n]+)[\s\t]*[\r\n]+/", "\n", $presidents);
Since it's an array you may need to loop through array elements though.

Answer 3

I didn't test this code, but it seems like a tighter way to accomplish the task. Just trim() and check for positive string length. I've added an element-limit to explode() and condensed your data storage syntax.
$file=fopen("namen2.txt","r");
$i=0; // initialize counter
while(!feof($file)){
$line=trim(fgets($file)); // get line and trim leading/trailing whitespaces from it
if(strlen($line)){ // if there are any non-whitespace characters, proceed
$names=explode(' ',$line,2); // max of two elements produced, in case: Martin Van Buren
// explode will fail to correctly split: John Quincy Adams
$presidents[]=['counter'=>++$i,'firstname'=>$names[0],'lastname'=>(isset($names[1])?$names[1]:'')]; // store the data for future processing
}
}
fclose($file);
foreach($presidents as $pres){
echo "Hey {$pres["firstname"]} {$pres["lastname"]}, du bist der {$pres["counter"]} Präsident der USA in meiner Liste.\n";
}