php how to use multidimensional array

Question

I want to do something like this

$cars = array('1', '2', '3', '4', '5', '6');
$cars = array('7', '8', '9', '10', '11', '12');
$cars = array('13', '14', '15', '16', '17', '18');

foreach ($cars as $car){
    echo $car[0].'<br />';
    echo $car[1].'<br />';
    echo $car[2].'<br />';
    echo $car[3].'<br />';
    echo $car[4].'<br />';
    echo $car[5].'<br />';
    echo '----------------<br />';
}

to get a result like this

1
2
3
4
5
6
----------------
7
8
9
10
11
12
----------------
13
14
15
16
17
18

I was hoping this code would work but I get errors like :Notice: Uninitialized string offset: 2 in C:\xampp\htdocs\....php on line 9

I have tried a lot of thing like $cars = array(array('1', '2', '3', '4', '5', '6')); but none of them worked for me, so please if anyone could help me with this one, I am new to php and I hope to learn more from you.

try $cars[] = array(... in your first 3 lines. (add [] after $cars). right now you are overwriting $cars each time. — Sean
– Sean, Commented Aug 8, 2015 at 15:17
Check out a tutorial on multidimensional arrays first. Then if you have a specific problem of why you code doesn't work ask that. Neither of your attempts suggest that you have tried this first. Your first attempt just redefines the variable in pretty much every programming language out there. The second attempt is closer. Try developphp.com/page.php?id=229 — scrappedcola
– scrappedcola, Commented Aug 8, 2015 at 15:18
@scrappedcola, I've watched like 5 tutorials, and none of them served what I needed to do! — Maria Bernal
– Maria Bernal, Commented Aug 8, 2015 at 15:25

rjdown · Accepted Answer · 2015-08-08 15:16:57Z

4

You are overwriting your array each time, rather than adding to it.

Try this:

$cars[] = array('1', '2', '3', '4', '5', '6');
$cars[] = array('7', '8', '9', '10', '11', '12');
$cars[] = array('13', '14', '15', '16', '17', '18');

This is the same as

$cars = array(
    array('1', '2', '3', '4', '5', '6'),
    array('7', '8', '9', '10', '11', '12'),
    array('13', '14', '15', '16', '17', '18')
);

answered Aug 8, 2015 at 15:16

rjdown

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3 Comments

Maria Bernal Over a year ago

Wow such a simple solution, and I was busting my mind over this, thank you awesome dude, you need to wait 9 minutes for the perfect answer!

trogne Over a year ago

@Maria Bernal, please see my answer. The specific error you got is not about overwriting.

rjdown Over a year ago

@trogne his looping is fine if the array is in the correct format, but it's not because (as above) he's overwriting rather than adding

Joey Evans · Accepted Answer · 2015-08-08 15:23:25Z

0

You need to understand that a 2 dimensional array is an array of arrays.

$cars1 = array('1', '2', '3', '4', '5', '6');
$cars2 = array('7', '8', '9', '10', '11', '12');
$cars3 = array('13', '14', '15', '16', '17', '18');
$cars2DArray = array($cars1, $cars2, $cars3)

foreach ($cars2DArray as $cars){
foreach($cars as $car){
echo $car.'<br>';
}
echo '----------------<br>'; }

answered Aug 8, 2015 at 15:23

Joey Evans

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Comments

mattslone · Accepted Answer · 2015-08-08 15:23:48Z

0

$cars = array(
    array('1', '2', '3', '4', '5', '6'),
    array('7', '8', '9', '10', '11', '12'),
    array('13', '14', '15', '16', '17', '18')
);

foreach ($cars as $sub) {
    foreach($sub as $item) {
        echo $item;
    }
}

You iterate through each array, then iterate through each item in those arrays.

answered Aug 8, 2015 at 15:23

mattslone

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Comments

Akshay · Accepted Answer · 2015-08-08 15:28:52Z

0

If you want to have a line break after every 6 numbers, here's an easy solution for you.

<?php

$cars = array();
$cars= array('1', '2', '3', '4', '5', '6','7', '8', '9', '10', '11', '12','13', '14', '15', '16', '17', '18');
$c=0;
foreach($cars as $car)
{
    if($c==6)
    {
        echo '----------------<br />';
        $c=0;
    }
    echo $car . "<br>";
    $c++;
}

?>

answered Aug 8, 2015 at 15:28

Akshay

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Comments

trogne · Accepted Answer · 2015-08-08 15:39:04Z

0

The Uninitialized string offset error is not because of overriding.

You get the same error with this :

$cars = array('1', '2', '3', '4', '5', '6');

foreach ($cars as $car){
    echo $car[0].'<br />';
    echo $car[1];
}

Here $car is not an array, it is the array value.

It will work for $car[0], cause php knows how to interpret the only value, but $car[1] doesn't exist (Uninitialized).

answered Aug 8, 2015 at 15:39

trogne

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1 Comment

rjdown Over a year ago

I think perhaps you missed the "multidimensional" part of the question.

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