PHP preg_match for empty lines

Question

I want to have an array of strings with <answers> and <names> tags from my xml file, (it's not guaranteed for file to be valid, so I can't parse it with simplexml)

after code execution I get an array with array[0] equal to something empty with lenght of 5, I thought that my regexp /^[\s\S]*$/ should remove all empty characters and lines, but on practice that array[0] element is stays the same as after array_filter.

how can I get this array without emty values?

array(8) { 
[0]=> 
string(5) " " 
[3]=> 
string(39) "<name>первый вопрос</name> " 
[4]=> 
string(68) "<answer id="1">Первый ответ на вопрос 1</answer> " 
[5]=> 
string(68) "<answer id="2">Второй ответ на вопрос 1</answer> " 
[6]=> 
string(68) "<answer id="3">Третий ответ на вопрос 1</answer> "
[9]=> 
string(51) "<name> второй вопрос</name> " 
[10]=> 
string(68) "<answer id="1">Первый ответ на вопрос 2</answer> " 
[11]=> 
string(68) "<answer id="2">Второй ответ на вопрос 2</answer> " 
}

I have xml file

<?xml version="1.0" standalone="yes"?> 
<test> 
<question id="1">
<name>первый вопрос</name>
<answer id="1">Первый ответ на вопрос 1</answer>
<answer id="2">Второй ответ на вопрос 1</answer>
<answer id="3">Третий ответ на вопрос 1</answer>
</question>
<question id="2">

<name>            второй вопрос</name>
<answer id="1">Первый ответ на вопрос 2</answer>
<answer id="2">Второй ответ на вопрос 2</answer>
</question>
</test>

and code

<?php
$xml = file_get_contents("test.xml");
$per = preg_replace('/<question[\s\S]+?>|<\/question>|<test>|
<\/test>|<\?xml[\s\S]+?>/i', "", $xml);
$array = explode("\n", $per);
function filter($str)
{
    return !preg_match('/^[\s]*$/', $str);
}

$array = array_filter($array, "filter");
var_dump ($array);
?>

http://stackoverflow.com/questions/3654295/remove-empty-array-elements — Claudio King, Mar 19 '16 at 10:48
@ClaudioKing this doesn't working, I can have empty values and whitespaces in array with lenght more than 1 — Alexander, Mar 19 '16 at 10:53
@bobblebubble this works great, but not on my server for some reason I get Warning: preg_match_all(): Compilation failed: PCRE does not support \L, \l, \N{name}, \U, or \u at ... — Alexander, Mar 19 '16 at 11:02
@Alexander did you use `~` as [delimiter](http://php.net/manual/en/regexp.reference.delimiters.php)? you can also escape the `\/` — bobble bubble, Mar 19 '16 at 11:09
@bobblebubble this works great thank you! if You write it as an answer I will accept it as one that solved my problem — Alexander, Mar 19 '16 at 11:14

mpyw · Accepted Answer · 2016-06-11T06:59:14.023

Simple one liner.

$array = array_filter(array_map('trim', file('example.xml')), 'strlen');

However, why do you use regular expressions to parse XML documents? I recommend you using native DOMDocument or SimpleXMLElement instead.

Example of DOMDocument:

$dom = new DOMDocument;
$dom->loadXMLFile('example.xml');
$xpath = new DOMXPath($dom);
$q2a1 = $xpath->evaluate('string(/question[@id="2"]/answer[@id="1"])');

Example of SimpleXMLElement:

$xml = new SimpleXMLElement('example.xml', 0, true);
$q2a1 = (string)$xml->xpath('/question[@id="2"]/answer[@id="1"]')->item(0);

score 0 · Answer 2 · answered Mar 19 '16 at 10:58

0

First replace all space or white space then check is empty if not return

function filter($str)
    {
        $string = preg_replace('/\s+/', '', $str);

        if($string !== ""):
           return $string;
        endif;
    }

    $array = array_filter($array, "filter");
    var_dump ($array);

answered Mar 19 '16 at 10:58

Misyaath Mohammed

7
3

this still get me to the array with first element [0]=> string(5) " " – Alexander Mar 19 '16 at 11:07

PHP preg_match for empty lines

2 Answers2