How do I use preg_match to test for spaces?

Question

How would I use the PHP function preg_match() to test a string to see if any spaces exist?

Example

"this sentence would be tested true for

Answer 1

How about using ctype_graph for this purpose? This would expand the scope of space to mean any "white space char" that does not print anything visible on screen (like \t, \n ) also. However this is native and should be quicker than preg_match.

$x = "string\twith\tspaces" ;
if(ctype_graph($x))
    echo "\n string has no white spaces" ;
else
    echo "\n string has spaces" ;