PHP array of arrays. Checkboxes to be ticked depending on inner array values

Question

I have arrays of Strings(that are each a combination of numbers "1" to "20") inside another array in PHP . I want to pre-tick the corresponding checkboxes (1 - 20) for each of my pages (these start at 0 and go on for potentially very many).This way the user can go to a page and see which boxes have been selected before.

For example:
Array [0] is {1, 2, 4} so these checkboxes should be checked when the user arrives at page 0.

This is what I have so far to try and get the values of the inner array:

foreach ($categoriesArr as $val) {
    if (is_array($val)) {
        foreach ($val as $innerVal) {
            // See which checkboxes are checked.
            if ($innerVal === "1") {
                $cb1 = true;
            } else {
                $cb1 = false;
            }
        }
    }
}

I know I can use <?php if ($cb1) echo "checked" ?> in the checkbox HTML to show it as ticked.
This is ok but it obviously loops through all the arrays and $cb1 will eventually end up as whatever the last arrays value is.
Should I introduce yet another array to store each individual pages checkbox values in? I am potentially dealing with thousands of entries so would like to keep any extra assignments to a minimum.

Answer 1

我建议使用保存页面索引的变量，然后将其包含在每个复选框中： <?php if(is_array($categoriesArr[$pageIndexVariable]) && $categoriesArr[$pageIndexVariable][$checkboxNameOrIdOrwhatever]) echo“ checked “？>