Foreach in PHP reverse process

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2

I have the following foreach():

$i = 1;
foreach($listagem as $valor){
echo $i; // O que vai me retornar: 1, 2, 3, 4, 5, ..., 100
$i++;
}

How do I do the reverse process? I would like to return: 100, 99, 98, 97, ..., 1

php
  • 1

    $i = 100; ...noose... $i--.

  • 1

    Explain better what you want to achieve because this is weird. Why $listagem if you only use the $i?

  • My idea is to assemble a count of records, as it is in list form.. in the order DESC, I would also enumerate in the order DESC

  • If the records come in descending order from the database just use one foreach normal that will already go through the records in reverse order

4 answers

7


I believe that’s it,

$i = 100;
foreach($listagem as $valor){
echo $i; // O que vai me retornar: 100, 99, 98 ...
$i--;
}

4

Initialize total item count

$i = count( $listagem );
foreach($listagem as $valor){
    echo $i; // 100, 99, 98, etc
    $i--;
}

  • has to be $i = Count( $listing ) -1; as it is -1 because of the 0 that the array starts

3

In your example it makes no sense to use a foreach, could normally use the for decreasing:

for($index = count($listagem); $index > 0; $index--) {
    echo $index;
}

And if you need to display items from array, in descending order as reported, just access the element:

for($index = count($listagem); $index > 0; $index--) {
    echo $listagem[$index];
}

  • I use foreah() to bring the database results, which are within the array ($listing)

1

I believe the doubt in our friend is not about displaying a variable in a decreasing sequence, but rather the contents of the array in descending order, so if there is an array with the contents:

$listagem = Array(1, 2, 3... 100);

he wants to show off:

100 99 98... 1

For this purpose the instruction itself "foreach" can be used as it will be possible to execute both for simple array and for array that index is named:

$listagem = Array('a' => 1, 'b' => 2, 'c' => 3... '???' => 100);

This should include instruction "array_reverse" so that the foreach (dry the contents as a queue), list the array in reverse order (as a stack structure), so the code can look like this:

foreach ( array_reverse($listagem) as $valor) {
  # Manipupação da variável $valor, ex:
  echo print_r($valor, true), '<br />';
}

Or, if you want to use the index:

foreach ( array_reverse($listagem) as $indice => $valor) {
  # Manipupação das variáveis $indice e $valor, ex:
  echo $indice, ':', print_r($valor, true), '<br />';
}

I hope I have not complicated too much with the explanations, and that the resolution is satisfactory the need.

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