Question

Let’s say I have the this text (not to be treated as PHP code):

$this->validation->set('username','username','trim');
$this->validation->set('password','password','trim');
$this->validation->set('password2','password2','trim');
$this->validation->set('name','name','trim');
$this->validation->set('surname','surname','trim');

I want to get the list of first words after set( which is in quotation marks in every line, so the output of previous input must be like this:

username
password
password2
name
surname

I think, it’s possible with regular expressions. My question is how can I get the list of the words which is in first quotation marks with PHP?

Answer 1

• Lets say the variable $text holds the data from your question.

• Let’s analyse the regular expression /set\('(.*?)'/:

  • / is the delimiter.

  • set\(' and ' are the strings set(' and ', respectively.

  • .*? is the least amount of (arbitrary) characters between the two aforementioned strings.¹

  • As a result, this regular expression matches:

    $this->validation->set('username','username','trim');

• To store all the strings you need in the array $matches[1], we can use the function preg_match_all.

  It suffices to call preg_match_all("/set\('(.*?)'/", $text, $matches).

¹ See also: Regex Tutorial – Repetition with Star and Plus – Laziness Instead of Greediness

Example code:

$text = <<<EOF
\$this->validation->set('username','username','trim');
\$this->validation->set('password','password','trim');
\$this->validation->set('password2','password2','trim');
\$this->validation->set('name','name','trim');
\$this->validation->set('surname','surname','trim');
EOF;
preg_match_all("/set\('(.*?)'/", $text, $matches);
print_r($matches[1]);