Is there a way to see invisible characters like whitespace, newlines, and other non-printing characters in a manner like print_r() ?
Reason is there is some sort of character in my array that I can't see and breaking things.
[name] => name
[numbers] => Array
 => 123
 => 456
 => 789
[action] => nothing
You can use the addcslashes function:
string addcslashes ( string $str , string $charlist )
which will return a string with backslashes before characters. An example would be:
<?php echo addcslashes('foo[ ]', 'A..z'); // output: \f\o\o\[ \] // All upper and lower-case letters will be escaped // ... but so will the [\]^_` ?>