How To Access Values In Associative Array Using PHP

问题

I have an array which is the result of a select query using Amazon SimpleDb.

Here is sample data when I print_r($result);

Array ( [0] => Array ( [Name] => 5140ede647e74
                       [Attributes] => Array (
                            [0] => Array ( [Name] => test_id [Value] => 5140ede647e74 )
                            [1] => Array ( [Name] => test_name [Value] => test1 )
                            [2] => Array ( [Name] => last_update [Value] => 1363209702 )
                            [3] => Array ( [Name] => created [Value] => 1363209702 ) ) ) )

If I want to extract the test_id and the test_name, how can I do it? I am currently doing the following

<?php foreach ($result as $item) {
    echo $item['Attributes'][0]['Value']; 
    echo $item['Attributes'][1]['Value'];
} ?>

But I want to do it by referencing "test_id" and "test_name" because when I delete the domain where the data resides and re-enter the data, the order of each attribute can change so I can't trust that $item['Attributes'][0]['Value'] will always be the test_id

Thanks!

回答1:

foreach ($result as $item) {
  foreach ($item['Attributes'] as $keyvalue) {
    if ($keyvalue['Name'] == 'test_id' || $keyvalue['Name'] == 'test_name') {
      echo $keyvalue['Value'];
    }
  }
}

回答2:

You need to recast the Array.

$newArray = array();
foreach ($result as $key=>$row)
{        
    foreach ($row['Attributes'] AS $row2)
    {
         $newArray[$key][$row2['Name']] = $row2['Value'];
    }       
}

EDIT: It depends on what you need to do - this is my preferred method if I plan on doing a lot of work with a resultset - I only need to iterate through the set once and then it's in a format where the data can be accessed quickly.

回答3:

The following will run trough the last part of your array by reference. Therefore edits that you make are reflected in the $result array.

foreach ($result[0]['Attributes'] as &$item) {
    if ($item['Name'] == 'test_id') // do something
}

来源：https://stackoverflow.com/questions/15399903/how-to-access-values-in-associative-array-using-php

标签

php

multidimensional-array

amazon-simpledb