Proper Syntax for PHP foreach function with associative arrays

Question

I have the following array named $ingredient_difference in PHP (example output below):

Array (
  [total_remaining_ingredients] => Array (
    [0] => 2 [1] => 3 [2] => 10
  )
  [idrecipe] => Array (
    [0] => 8 [1] => 10 [2] => 9
  )
  [value] => Array ( [0] => 1 [1] => 1 [2] => 1 )
)

I'm trying to extract at least the values of idrecipe using 'foreach', but I'm getting undefined index with the following code:

foreach($ingredient_difference as $recipe_output)
{
    echo $recipe_output['idrecipe']."<br />";
}

I know the above isn't exactly the way to do it, but this also was not working (undefined index error for 'idrecipe', 'value' and 'total_remaining_ingredients'):

foreach($ingredient_difference as $c => $rowkey)
{
    $sorted_idrecipe[] = $rowkey['idrecipe'];
    $sorted_value[] = $rowkey['value'];
    $sorted_remaining_ingredients[] = $rowkey['total_remaining_ingredients']; 
}

What am I missing in my foreach syntax? Or is there a better way?

This foreach construct is also giving undefined index errors:

foreach($ingredient_difference as $rowkey => $index_value)
{
    $id_value[$key] = $index_value['idrecipe'];
    $value_value[$key] = $index_value['value'];
    $tri_value[$key] = $index_value['total_remaining_ingredients'];
}

Answer thanks to ComFreek:

$result_ingredient_difference = array();
$count_id = count($ingredient_difference['idrecipe']);

for ($i=0; $i<$count_id; $i++)
{
  $result_ingredient_difference[] = array(
  'tri' => $ingredient_difference['total_remaining_ingredients'][$i],
  'idrecipe' => $ingredient_difference['idrecipe'][$i],
  'value' => $ingredient_difference['value'][$i]
  );
}
//rearranged array of $result_ingredient_difference able to call proper indexing with the below
foreach($result_ingredient_difference as $rowkey => $index_value) 
{ 
  $id_value[$key] = $index_value['idrecipe']; 
  $value_value[$key] = $index_value['value']; 
  $tri_value[$key] = $index_value['tri'];
}

ComFreek · Accepted Answer · 2012-04-24 14:20:28Z

4

With your first foreach() loop, you iterate over the main array and not over the values of the subarray idrecipe!

foreach($ingredient_difference['idrecipe'] as $value)
{
  echo $value;
}

edited Apr 24, 2012 at 14:20

answered Apr 24, 2012 at 14:09

ComFreek

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4 Comments

Jay C. Besch Over a year ago

Thanks. That definitely gets the 'idrecipe' value. How would I go about getting the three different indices (i.e., 'idrecipe', 'value', and 'total_remaining_ingredients'). I thought using something like foreach($ingredient_difference as $key => $value) does the trick, but I haven't had any success.

ComFreek Over a year ago

What do you want to do exactly? It's not neccessary if you have only three entries. Your foreach() is right but I think you access the specific values in the wrong way. Show us the code, please.

Jay C. Besch Over a year ago

Instead of running three different foreach loops for the 'idrecipe', 'value', and 'total_remaining_ingredients' indices, I wondered if there was a way to construct only one foreach loop to get the values for all three. See amended code above, which is giving me undefined index errors.

Jay C. Besch Over a year ago

Yes - I think that will do the trick. I'll post my results after testing. Thank you.

PascalPflaum · Accepted Answer · 2012-04-24 14:18:07Z

foreach constructs a loop. In your code

foreach($ingredient_difference as $recipe_output) {
echo $recipe_output['idrecipe']."<br />"; }

in the first loop run: $recipe_output is $ingredient_difference[total_remaining_ingredients] in the second loop run: $recipe_output is $ingredient_difference[idrecipe] in the third loop run: $recipe_output is $ingredient_difference[value]

because there is no

$ingredient_difference['total_remaining_ingredients']['idrecipe']
$ingredient_difference['idrecipe']['idrecipe']
$ingredient_difference['value']['idrecipe']

you get the error.

to see how the foreach loop works use the examples on http://php.net/manual/de/control-structures.foreach.php

i Expect what you want to do is:

foreach($ingredient_difference['idrecipe'] as $value_of_recipe)
{
    echo $value_of_recipe."<br />";
}

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