打印多维数组

I have this code in PHP:

$rules = array(
    "s0" => array(
        "a" => "s1_s2_s3",
        "b" => "s2_s3"    
    ),
    "s1_s2" => array(
        "a" => "s1_s2",
        "b" => "s2_s3"
    ),
);

And want to print it like this:

s0 -- a --- s1_s2_s3
s0 -- b --- s2_s3
s1_s2 -- a --- s1_s2
s1_s2 -- b --- s2_s3

How do I do it?

This is how you do it:

$rules = array(
    "s0"  => array(
        "a" => "s1_s2_s3",
        "b" => "s2_s3"
    ),
    "s1_s2" => array(
        "a" => "s1_s2",
        "b" => "s2_s3"
    ),
);


foreach ($rules as $key => $args) {
    foreach ($args as $key2 => $vals) {
        print $key . ' -- ' . $key2 . ' --- ' . $vals . '<br>';
    }
}

To edit the array

You would use array_push or [].

array_push($rules, ['another' => ['c' => 'value']]);
$rules['another'] = ['c' => 'value']];

To add or update to the array at an index:

$rules['another']['c'] = 'change c value';

To achieve this you have to traverse the array. To do this, you need a loop, and in PHP, there is a function foreach. Here is the example-

Given array:

$rules = array("s0" => array("a" => "s1_s2_s3",
                              "b" => "s2_s3"    
                              ),
               "s1_s2" => array("a" => "s1_s2",
                                "b" => "s2_s3"
                               )
                );

foreach ($rules as $key => $value) {
    foreach ($value as $sub_key => $sub_val) {
        echo "<p>".$key." -- ".$sub_key." --- ".$sub_val."</p>";
    }
}

The foreach construct provides an easy way to iterate over arrays.

Output:

s0 -- a --- s1_s2_s3
s0 -- b --- s2_s3
s1_s2 -- a --- s1_s2
s1_s2 -- b --- s2_s3