Regular Expressions 101

^start of string

Negated Character Class[^\s/\#6]{221}

{221}matches exactly 221 characters outside the set below:

\sany whitespace character

/the literal / (47₁₀ / 57₈ / 2F₁₆)

\#the literal # (35₁₀ / 43₈ / 23₁₆)

6the literal 6 (54₁₀ / 66₈ / 36₁₆)

$end of string, or before its final line terminator

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

^[^\s/\#6]{221}$

New

<?=(function($n,$snake){foreach(array_chunk(range(1,$n*$n),$n)as$i=>$a){if($i%2)$a=array_reverse($a);echo"\n",join('',array_map(function($e){return(sprintf("%3d",$e));},$a));}})($argv[1],'-=-=-=-=-=-=-=-=-=-=-=-=-=-o~')?>

Regular Expression

Substitution