reading data from multidimensional array

shish1 · July 2nd, 2003, 05:24 PM

i am trying to read info from a multidimensional array but can't seem to get anything from it. Here is a snippet of the code i'm using:

$pictures = array (
    array ("dodder", "All from the Dodder"),
    array ("drawings", "Drawings of Wildlife"),
    array ("garbage", "Stuff and more stuff")
);

echo "$pictures[2][1]";

Now this should (i thought) echo out "Stuff and more stuff" but instead it the browser says 'Array[1]' Any idea what i'm doing wrong? Thanks.

nikolai · July 2nd, 2003, 06:44 PM

Okay, you're doing a few things wrong.

First of all, you don't HAVE any numerical indexes defined in your inner arrays. You only have the string indexes "dodder", "drawings", and "garbage".

2nd of all, the fact that you're trying to access index 1 in an array that only contains one item implies that you believe PHP arrays are 1-indexed. They're not. The first automatically assigned numerical index in an array is 0.

The $pictures[2][1] should most likely be $pictures[2]['garbage'].

Lastly, you've enclosed $pictures[2][1] in a string. PHP performs variable substitution within double-quoted strings up to a point; it doesn't handle nested arrays.

What's happening is that PHP sees "$pictures[2]" and tries to substitute THAT value into the string, then prints out the "[1]" after it. Since $pictures[2] is an array, PHP just substitutes the string "Array" for it's value.

Since you're not echoing anything else, just drop the quotes:

echo $pictures[2]['garbage'];

If you need the quotes, use curly-brace syntax for nested arrays:

echo "The item is {$pictures[2]['garbage']}.";

For more info on string parsing, read the manual at:
http://www.php.net/types.string#lang....syntax.double

You should also make heavy use of the print_r() and/or var_dump() functions. They display the contents of your variables, including all key/value pairs in an array.

For example:

Code:

// using your $pictures from above:

echo "<pre>\n";
print_r($pictures);
echo "</pre>\n";
?>

would result in something like the following output:

Code:

Array:
(
   [0]  =>  Array:
      (
          [dodder]  =>  "All from the Dodder"
      )
   [1]  =>  Array:
      (
          [drawings]  =>  "Drawings of Wildlife"
      )
   [2]  =>  Array:
      (
          [garbage]  =>  "Stuff and more stuff"
      )
)

Hope this helps!

Take care,

Nik
http://www.bigaction.org/

shish1 · July 3rd, 2003, 04:40 AM

Nik,

thanks for the reply. the code i gave was just a small part of a huge array, so referring to the elements by name wasn't practical. i ended up solving the problem by simply putting braces around the the string. so, instead of:

echo "$pictures[2][1]";

I used:

echo "{$pictures[2][1]}";

And it displayed the page just as i needed. The first half of the array was a .jpg name and the second half was a caption. it ended up mkaing a brilliant photo album. Thanks for your help though - very appreciated.:D

nikolai · July 3rd, 2003, 12:36 PM

Again, if you aren't echoing anything else out within your double-quoted string, there's really no reason to enquote your variable. When PHP sees the double quoted string, it goes into string-parsing mode. When it sees a { followed by a $, it drops back into variable parsing mode until it sees the }.

The whole thing could simply be rewritten as:

echo $pictures[2][1];

And PHP won't incur the tiny additional processing overhead as the original version. It's not a big deal, I know, but the simpler version is (imho) much easier to read.

Either way, I'm glad it's working!

Take care,

Nik
http://www.bigaction.org/

nealw · April 1st, 2007, 06:42 PM

I am having a similar problem of extracting values from an array that was parsed from an XML file...perhaps someone can point me in the right direction.

I have a parser put together that outputs the array below. What I am having problems with is getting the values into php friendy variables so I can display the content. I am also including a "work in progress" piece of code where I am trying to loop through the array to get at the values...but I am stuck on the right format to out put the content of the array!

Array output of XML feed:

Code:

 
Array
(
    [SPECIALS] => Array
        (
            [SPECIAL] => Array
                (
                    [0] => Array
                        (
                            [ID] => 2114
                            [TITLE] => COZUMEL - Allegro Cozumel ~ July 1 - August 31, 2007
                            [THUMBNAIL] => http://www.mysite.com/upload/file_16183.jpg
                            [SALESEND] => Apr 03, 2007
                            [ADVNIGHTS] => 5
                            [LOCALEID] => 322
                            [LOCALENAME] => Cozumel
                            [ADVERTISEDPRICE] => 949.00
                            [TRAVELDATESINFO] => July 1 - August 31, 2007
                            [ADDITIONALINFO] => All Inclusive ~ Kids Stay & Eat Free
                        )

                    [1] => Array
                        (
                            [ID] => 2113
                            [TITLE] => COZUMEL - Allegro Cozumel ~ May 1 - June 30 & September 1 - October 31, 2007
                            [THUMBNAIL] => http://www.mysite.com/upload/file_16183.jpg
                            [SALESEND] => Apr 03, 2007
                            [ADVNIGHTS] => 5
                            [LOCALEID] => 322
                            [LOCALENAME] => Cozumel
                            [ADVERTISEDPRICE] => 879.00
                            [TRAVELDATESINFO] => May 1 - Jun 30 & Sep 1 - Oct 31, 2007
                            [ADDITIONALINFO] => All Inclusive ~ Kids Stay & Eat Free
                        )

                )

        )

)

Get the file contents of the array: This is where I am having a problem?

Code:

 

// Get the file contents 
$myar=getXmlData2($contents); 
for($i=0;$i<=count($myar[SPECIALS][SPECIAL]);$i++) { 
// Here, we want to read the TITLE, SUMMARY, and THUMBNAIL etc. of the XML feed. 

$id = $myar[ID][$i]; 
$title = $myar[TITLE][$i]; 
$thumbnaillink = $myar[THUMBNAIL][$i]; 
$saleends = $myar[SALESEND][$i]; 
$advnights = $myar[ADVNIGHTS][$i]; 
$localeid = $myar[LOCALEID][$i]; 
$localename = $myar[LOCALENAME][$i]; 
$adverpprice = $myar[ADVERTISEDPRICE][$i]; 
$pricedoubleroom = $myar[TRAVELDATESINFO][$i]; 
$salesend = $myar[ADDITIONALINFO][$i]; 
$summary = $myar[SUMMARY][$i]; 

//echo " <b>$id</b> $title $summary <br><br>"; 
} 
?>

Any suggestions would be appreciated!

Thanks,

Neal