使用PHP正则表达式解析XML

Question

How can I use a regular expression to parse XML?

Let's suppose we have the following:

$string = '<z>1a<z>2b</z>3c<z>4d</z>5e</z>';
preg_match_all('/<z>(.+)<\/z>/', $string, $result_a);
preg_match_all('/<z>(.+)<\/z>/U', $string, $result_b);
preg_match_all($regex, $string, $result_x);

If I run that, then $result_a will have the string (among the items of the array):

'1a<z>2b</z>3c<z>4d</z>5e'

In addition, variable $result_b will have the strings (among the items of the array):

'1a<z>2b'
'4d'

Now, I want $result_x to have '2b' and '4d' separately, among the items of the array.

What should $regex look like?

Thanks in advance!!!

Answer 1

Use non-greedy quantifier:

'/<z>(.+?)<\/z>/'
     ___^

or change the dot by a negative character class:

'/<z>([^z]+)<\/z>/'

or

'/<z>([^<>]+?)<\/z>/'

or, much more convenient, use a xml parser

Answer 2

In this case you can either use a non-greedy quantifier or you can use this alternative regex:

'/<z>([^<]+)<\/z>/'

[^<] captures all characters except < .