字符类中的单词

Question

In a character class can I match full words?

Using this code, the regular expression removes the {else} tag, so is it possible to add else inside of the character class as a word, and not as 4 letters?

$section = "
{if {money} == 'yes'}
   Sweet!
{else}
    Too bad...
{/if}
";

echo preg_replace("/\{[^ \/]+\}/iU", "''", $section);

I thought that this might work (but it doesn't):

echo preg_replace("/\{[^ (else)\/]+\}/iU", "''", $section);

Expected output:

{if '' == 'yes'}
   Sweet!
{else}
    Too bad...
{/if}

Answer 1

No. You absolutely can not place words inside of a character class [].

But you can use a Negative Lookahead here instead.

$section = <<<DATA
{if {money} == 'yes'}
   Sweet!
{else}
    Too bad...
{/if}
DATA;

$section = preg_replace('~\{(?!else|/)\S+\}~i', "''", $section);
echo $section;

See Live demo

Regular expression:

\{            '{'
 (?!          look ahead to see if there is not:
  else        'else'
  |           OR
  /           '/'
 )            end of look-ahead
  \S+         non-whitespace (all but 
, , \t, \f, and " ") (1 or more times)
\}            '}'