add white spaces between characters and special symbol in PHP
<p>I am newbie of php, i want to know how to add whitespace between character and symbol or symbol and symbol, for example, the original string is “[PDF format(29.71MB)]“, how can i use function preg_replace or other method to represent the result as “[ PDF format (29.71MB) ]“?
i.e, I want to leave the space between symbol "[" and character "P" and also ")" and "]"</p>

<p>Many thanks</p>

<p>Simon</p>
