PHP two-dimensional array with empty items

Question

With a lot of help of another user I came to the point that I get the two-dimensional array I desired. Every ID i get ($talente) saves a line from the CSV. Works like a charm for the array. But the output confuses me.

This is the CSV I use:

Schild,1,Licht,1w10,-
Schutz,1,Licht,1w10,-
Licht,4,Licht,1w10,-
Genesung,1,Licht,-,-
Aufopfern,1,Licht,-,-

The script:

<?php

$talente = $_GET['talente'];

$myFile = fopen("talente.csv", "r");
$csv = [];
while ($data = fgetcsv($myFile, 1000, ",")) {
    $csv[] = $data;
}
fclose($myFile);

        $talentline = array_filter($csv, function($i) use ($talente) {
            return in_array($i, $talente);
        }, ARRAY_FILTER_USE_KEY);


print_r(array_values($talentline));

echo $talentline[1][0];
echo $talentline[2][0];    //line 21.
echo $talentline[3][0];

?>

print_r(array_values($talentline)); gives me the following output for the id's 1 & 3.

[0] => Array (
    [0] => Schutz
    [1] => 1
    [2] => Licht
    [3] => 1w10
    [4] => -
    )
[1] => Array (
    [0] => Genesung
    [1] => 1
    [2] => Licht
    [3] => -
    [4] => -
    )

The three echos at the end give me this:

Schutz Notice: Undefined offset: 2 in C:\xampp\htdocs\DvC Generator\php\test.php on line 21 Genesung

There are two issues I can't work out. The first one is, that the printed lines are one line after the one I'd expect. So instead of "Schutz" I'd expect "Schild".

The bigger issue I have is, that the script saves the line at the array-position equal to the ID. That's not what I need, because it saves empty array elements as well. My desired outcome would be Schild at array[0] and Licht at array[1] when the IDs 1 and 3 were send.

I hope I could explain it well enough.

edit your question to state that. Also state what is the value of $_GET['talente']? — Mm-Art-In
– Mm-Art-In, Commented Aug 28, 2016 at 11:57
Your current in_array searches $i (which is index as you use USE_KEY) in a $talente (which is a string I suppose). So how do you think - what will happen when you will try to search 0 in a string? — u_mulder
– u_mulder, Commented Aug 28, 2016 at 11:59

Mm-Art-In · Accepted Answer · 2016-08-28 12:38:34Z

1

Array values start counting at `0`

So zero is first, and 1 is second.

Your issue of "undefined Offset" is caused because you are only "keeping" the array values that are found in the $_GET['talente'] input array. If you change this value to 2 then you will get undefined offset notices for 1 and 3, etc.

Your First issue is that arrays start at [0] so if you have two values in the new talentline array then the first is key [0] and the second value is key [1]. etc.

Your second issue is related in that because you're comparing the key values in the anonymous function, you are looking for the first value (array key [0]) by asking for value number 1 as given by the $_GET array. This is why it's giving you the uexpected (but correct) results.

Solutions:

For the second issue (which is a coding bug):

You need to adjust the key value by either increasing the key values by +1 or to decrease the input reference values by -1, to make the input align with the given CSV values:

return in_array($i, $talente--); //reduces the input comparison value by 1, 
         //so that the first value ("1") is treated as key "0".

Second, To fix the notice you get from referencing an unset array reference later in the script:

print isset($talentline[2][0]) ? $talentline[2][0]; : ""; 
// shorthand PHP stating that if value is set then print it, 
// else don't print anything.

Code I used to reach this answer (PHP 5.6.2). Obviously, adjusted as I don't have your CSV file to import, etc.

<?php
$talente = array(0=>1,1=>3);

$csv[] = array(0=>"Schild", 1=>1, 2=>"Licht", 3=>"1w10", 4=>"-");
$csv[] = array(0=>"Schutz", 1=>1, 2=>"Licht", 3=>"1w10", 4=>"-");
$csv[] = array(0=>"Licht", 1=>4, 2=>"Licht", 3=>"1w10", 4=>"-");
$csv[] = array(0=>"Genesung",1=>1,2=>"Licht",3=>"-",4=>"-");
$csv[] = array(0=>"Aufopfern",1=>1,2=>"Licht",3=>"-",4=>"-");

        $talentline = array_filter($csv, function($i) use ($talente) {
            return in_array($i, $talente--);
        }, ARRAY_FILTER_USE_KEY);
        $talentline = array_filter($talentline);

print_r(array_values($talentline));

print isset($talentline[1][0]) ? $talentline[1][0]; : ""; 
print isset($talentline[2][0]) ? $talentline[2][0]; : ""; 
print isset($talentline[3][0]) ? $talentline[3][0]; : "";

edited Aug 28, 2016 at 12:38

answered Aug 28, 2016 at 12:14

Mm-Art-In

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2 Comments

Kendel Ventonda Over a year ago

Thank you a lot for your help and your explanations! But I think I couldn't explain what I try to do here. If the user would set ID 4 and 5 ($talente = array(0=>4,1=>5);) I'd get nothing printed since Genesung and Aufopfern were ignored. I need $talentline[1][0] filled with the first fitting line of the CSV. I hope it's understandable what I mean.

Kendel Ventonda Over a year ago

Okay I got it. I noticed that "array_values" is doing exactly that and yeah, just had to give it to $talentline. Thank you!

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