使用正则表达式从文本中获取多个字符串[关闭]

Question

I have the following set of strings in a PHP file.

echo '<div class="alert"><b>',__('ERROR!'),'</b> ',__('Please fix following errors!'),'</div>';
echo sprintf(__('hello %s'), $name);
___('Hello');

__() function returns string and ___() function echo's a string. I have written a regex to grab text in between __('') or ___('') but it's not working properly.

Here is my regex

if(preg_match_all("#(__{2,3}(\((.*)\),|;))#",$text, $matches))

and output I get is:

__('ERROR!'),' ',__('Please fix following errors!'), (Incorrect result)
__('hello %s'),

For the ___() function I am using quantifier _{2,3} but it's not picking up this function. How do I get the string only from the functions?

Answer 1

You are using __{2,3}. a{n,m} repeats the previous item between n and m times. So __{2,3} matches an underscore followed by 2 or 3 underscores. You're trying to match an underscore repeated 2 or 3 times, so use _{2,3} instead.

Then, you're using ,|; to match a comma or a semicolon. This does not work as you expect. | is used to specify alternatives. For example, (foo|bar) matches either foo or bar. In your regex, you're using (\((.*)\),|;), and this will mean match \((.*)\), or ; -- which is not what you want. To match a , or ;, use a character class -- [,;].

(.*) is greedy and will match as many characters as possible. If you use the regex a.*c on a stringabcabc, it will match the whole string abcabc. But a.*?c will only match the first abc. By adding the ? after the *, we tell it to repeat as few times as possible.

The correct regular expression would be:

preg_match_all('#_{2,3}\([\'"](.*?)[\'"]\)[,;]#', $text, $matches);

Regex101 demo.