如何在php表单处理器中获取多组复选框值？

Question

Looking everywhere, but can't find solution. Everyone talks about one group like so:

<input type="checkbox" value="red" name="colors[]"> red<br />
<input type="checkbox" value="purple" name="colors[]"> purple<br>
<input type="checkbox" value="blue" name="colors[]"> blue<br>
<input type="checkbox" value="black" name="colors[]"> black<br>

but i am needing to do multiple groups in a single form like this:

<input type="checkbox" value="red" name="colors[]"> red<br />
<input type="checkbox" value="purple" name="colors[]"> purple<br>
<input type="checkbox" value="blue" name="colors[]"> blue<br>
<input type="checkbox" value="black" name="colors[]"> black<br>
<input type="checkbox" value="sm" name="sizes[]"> small<br />
<input type="checkbox" value="med" name="sizes[]"> medium<br>
<input type="checkbox" value="lrg" name="sizes[]"> large<br>
<input type="checkbox" value="xlrg" name="sizes[]"> x-large<br>

and on top of that the form is dynamic. the names are variable and unknown, so in php post code, it can't be $_POST['colors'].

i have this snippet which can grab all unknown names and build a message for later inserting into an email script for emailing the values of submitted form:

foreach ($_POST as $field=>$value) {
    if ($field != "submit") $msg .= $field . ": " . $value . "
";
}

but as you probably know, when it gets to a set of checkboxes, it says the value is "array", so not only does it need to split or implode the array into multiple values for checkboxes, it then needs to do that for multiple groups of checkboxes.

so for example this might be what $msg would be on a particular form:

first_name: first
last_name: last
email_address: [e-mail]
phone: [phone]
variable_radio_name: answer
variable_selectbox_name: answer
colors_from_checkbox_group_one: red,blue
sizes_from_checkbox_group_two: med,lrg
variable_textarea_name: blah blah blah

textboxes, textareas, radios, dropdown boxes are all easy because it's one answer a piece, but those checkboxes are a pain.

EDIT

did it like this:

if ($field != "submit") $msg .= $field . ": " . is_array($value) ? implode(',', $value) . "
" ? $value . "
";

and like this:

if ($field != "submit") {
    $msg .= $field . ": " . is_array($value) ? implode(',', $value) . "
" ? $value . "
";
}

syntax error both ways.

Answer 1

Your syntax error is in using ? twice instead of : for the send part of the ternary. Also, you need parentheses to make the concatenation work correctly:

$msg .= $field . " : " . (is_array($value) ? implode(',', $value) . "
" : $value . "
");

This might be more readable:

if ($field != "submit") {
    if(is_array($value)) {
        $msg[] = "$field : " . implode(',', $value);
    } else {
        $msg[] = "$field : $value";
    }
}
$msg = implode("
", $msg);