function trimchars($chars, $subject)
{
  return preg_replace("/\s*([$chars])\s*/", '\1', $subject);
}

#                 V
# a b c d e => a bcd e
trimchars('c', 'a b c d e');

#                  V V
# 23 + 2 = 25 => 23+2=25
trimchars('+=', '23 + 2 = 25');

#     V          V    V     V    V
# body{background:#fff;color:#fff;}
trimchars('{}:;', 'body { background: #fff; color: #fff; }');

function trimchars($chars, $subject)
{
  return preg_replace("/\s*([$chars])\s*/", '\1', $subject);
}

#                 V
# a b c d e => a bcd e
trimchars('c', 'a b c d e');

#                  V V
# 23 + 2 = 25 => 23+2=25
trimchars('+=', '23 + 2 = 25');

#     V          V    V     V    V
# body{background:#fff;color:#fff;}
trimchars('{}:;', 'body { background: #fff; color:#fff; }');

Looks for $chars in $subject and removes any preceding and succeeding whitespace from the provided characters. It works much like trim(), except it trims characters instead of the string itself.

Trim characters

PHP