Pangrams problem from https://www.hackerrank.com/challenges/pangrams

Pangrams.php

<?php
$_fp = fopen("php://stdin", "r");
while($line=fgets($_fp)){
    $line = strtolower($line);
    $line_length = strlen($line);
    $char_ar=array();
    for ($i=0;$i<$line_length;$i++){
        $current_char = $line[$i];
        if(preg_match('/^[a-z]$/',$current_char)){
            $char_ar[$current_char] = 1;
        }
        if(count($char_ar)==26) {
            break;
        }
    }
    if(count($char_ar)==26){
        echo "pangram";
    }
    else{
        echo "not pangram";
    }
}
fclose($_fp);
?>

Python Solution

s = input().lower()
if len([x for x in list(set(s)) if x.isalpha()])==26:
    print("pangram")
else:
    print("not pangram")