Why isn't php explode extracting array values

Question

I have some date values (each with a trailing = sign) stored as a &-delimited string.

My $_POST['dates'] string looks like this:

23.08.18=&22.08.18=&21.08.18=

I'm trying the following PHP code to extract the dates before inserting them into my database table. The code is currently not working.

foreach(explode('&', $_POST['dates']) as $value)  
{
    $value1 = explode('=', $value);
    foreach ($value1 as $x) {
    }
}

How can I isolate the date values?

Clarification: The problem is that the variables $value1 and $x are empty — objelland, Aug 09 '18 at 02:37
Possible duplicate of [Explode that doesn't return empty strings?](https://stackoverflow.com/questions/64570/explode-that-doesnt-return-empty-strings) — Yohanes Gultom, Aug 09 '18 at 02:55
What is your exact expected result? How might your input data vary? Might you have duplicate dates? — mickmackusa, Aug 09 '18 at 02:57

mickmackusa · Answer 1 · 2018-08-10T04:30:21.917

The function that you might be looking for is parse_str(). You have a valid query string (well, kind of) with keys but no values, so you merely need to parse it and isolate the keys(dates). Unfortunately, the parser converts your dots to underscores.

Code: (Demo)

$string = '23.08.18=&22.08.18=&21.08.18=';
parse_str($string, $out);
var_export(array_keys($out));

Output:

array (
  0 => '23_08_18',
  1 => '22_08_18',
  2 => '21_08_18',
)

And of course, you can repair the modified date values with str_replace(). See this demo.

Or if you want to disregard parse_str(), you can use just one regex call that divides the string on = followed by an optional &:

Code: (Demo)

$string = '23.08.18=&22.08.18=&21.08.18=';
var_export(preg_split('~=&?~', $string, -1, PREG_SPLIT_NO_EMPTY));

Output:

array (
  0 => '23.08.18',
  1 => '22.08.18',
  2 => '21.08.18',
)

Or without regex, just trim the last = and explode on =&: (Demo)

$string = '23.08.18=&22.08.18=&21.08.18=';
var_export(explode('=&', rtrim($string, '=')));
// same output as preg_split()

@objelland I would appreciate if you would re-compare the answers on this page. — mickmackusa, Aug 10 '18 at 12:37

Khoa TruongDinh · Accepted Answer · 2018-08-10T04:11:27.643

0

<?php

$data = '23.08.18=&22.08.18=&21.08.18=';

//$delimiters has to be array
//$string has to be array

function multiexplode ($delimiters,$string) {

 $ary = explode($delimiters[0],$string);
 array_shift($delimiters);
 if($delimiters != NULL) {
    foreach($ary as $key => $val) {
        $ary[$key] = multiexplode($delimiters, $val);
    }
 }
 return  $ary;
}

$exploded = multiexplode(array("=","&"),$data);

var_dump($exploded);

The result should be:

array (size=3)
  0 => string '23.08.18' (length=8)
  2 => string '22.08.18' (length=8)
  4 => string '21.08.18' (length=8)

We need to use array_filter.

http://php.net/manual/en/function.explode.php

[EDIT] mickmackusa's answer is the right tool for parse url parameters into variables.

edited Aug 10 '18 at 04:11

answered Aug 09 '18 at 02:48

Khoa TruongDinh

913
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Your proposal solved my problem, great stuff! After running the multiexplode function I just added a foreach loop to extract the content of the array. – objelland Aug 09 '18 at 03:06
1

@objelland don't multi-explode anything. This answer is an inefficient hack that can be completely replaced with two native function calls. – mickmackusa Aug 09 '18 at 03:17

Why isn't php explode extracting array values

2 Answers2