Foreach和nth术语

Question

我试图将内容打印成三列，这意味着我需要检索与术语3n-2匹配的记录。我该怎么做..。也许用模数？谢谢!

foreach($grid as $tile):
    echo '<div class="tile"><img src="/media/full/' . $tile['source'] . '"/></div>';
endforeach;

Answer 1

我想你要找的只是一个额外的柜台：

$i=0;
foreach($grid as $tile) {
    if($i++ % 3 == 0) {
        //do something every 3rd time
    }
    //do something every time
}

Answer 2

我想你是在寻找这样的东西：

(示例代码，只需使用$arr更改$grid)

<?php

    $arr = array(1, 2, 3, 4, 5, 6, 7, 8, 9);

    for($count = 0; $count < count($arr); $count++) {

        if($count % 3 == 0 && $count != 0)
            echo "<br />";
        echo    $arr[$count];

    }


?>

输出：

123
456
789

或者，如果希望将列放在单独的数组中：

<?php

    $arr = array(1, 2, 3, 4, 5, 6, 7, 8, 9);
    $columnOne = array();
    $columnTwo = array();
    $columnThree = array();

    for($count = 0; $count < count($arr); $count++) {

        if($count % 3 == 0)
            $columnOne[] = $arr[$count];
        elseif($count % 3 == 1)
            $columnTwo[] = $arr[$count];
        else
            $columnThree[] = $arr[$count];

    }

    print_r($columnOne);
    print_r($columnTwo);
    print_r($columnThree);

?>

输出：

Array ( [0] => 1 [1] => 4 [2] => 7 )
Array ( [0] => 2 [1] => 5 [2] => 8 )
Array ( [0] => 3 [1] => 6 [2] => 9 )

Answer 3

是的，如果我正确理解您的意思，我将使用模php操作符%：

<?php
  $grid = array(1,2,3,4,5,6,7); # just for testing

  $n = 1;
  foreach($grid as $tile) {
    if (($n + 2) % 3 == 0) {
      #echo '<div class="tile"><img src="/media/full/' . $tile['source'] . '"/></div>';
      echo "$n\n"; # just for testing
    }
    $n++;
  }
?>

它产生：

$ php x.php 
1
4
7