How to access the array via the function php

[padana]

<?php

function evaluate($expression)
{
    // TODO : add rendering code here

   
}

// 100 + 200 + 300
$expression1 = [
    "type" => "add",
    'children' => [
        [
            "type" => "number",
            "value" => 100
        ],
        [
            "type" => "number",
            "value" => 200
        ],
        [
            "type" => "number",
            "value" => 300
        ]
    ]
];

// 100 + 2 * (45 +5)
$expression2 = [
    "type" => "add",
    'children' => [
        [
            "type" => "number",
            "value" => 100
        ],
        [
            "type" => "multiply",
            "children" => [
                [
                    "type" => "number",
                    "value" => 2
                ],
                [
                    "type" => "add",
                    "children" => [
                        [
                            "type" => "number",
                            "value" => 5
                        ],
                        [
                            "type" => "number",
                            "value" => 45
                        ]
                    ]
                ]
            ]
        ]
    ]
];



// 1 + 100 / 1000
$expression3 = [
    "type" => "add",
    'children' => [
        [
            "type" => "number",
            "value" => 1
        ],
        [
            "type" => "fraction",
            "top" =>
            [
                "type" => "number",
                "value" => 100
            ],
            "bottom" =>
            [
                "type" => "number",
                "value" => 1000
            ]
        ]
    ]
];

echo "Expression 1 evaluates to: " . evaluate($expression1) . " <br>";

echo "Expression 2 evaluates to: " . evaluate($expression2) . " <br>"
 
echo "Expression 3 evaluates to: " . evaluate($expression3) . " <br>"

 

[ginerjm]

Yes?  What is your question?  And - is this some kind of homework?

My guess is you access an array with php code.  Have you written any yet this semester?

PS - are you studying recursion at this time?

 

Edited September 17, 2021 by ginerjm

[padana]

yes it's a duty I am blocked. Because I want to get the value back but he gives me that

 foreach ($expression as $i) {
        $var1 = var_dump($i[0]["value"]);
        $var2 = var_dump($i[1]["value"]);
        $var2 = var_dump($i[2]["value"]);

result: Warning: Illegal string offset 'value'

[ginerjm]

Blocked?   Look closely at your expression contents.  Then figure out what level of that multi-dimension array you want to access.  You are currently assuming that $i has numeric indices.  No.  It has 2 named elements - 'type' and 'children'.   Work with that knowledge

[padana]

 

here for expression1 I found the result:

  $var1 = $expression['children'][0]['value'];
    $var2 = $expression['children'][1]['value'];
    $var3 = $expression['children'][2]['value'];
    return $var1 + $var2 + $var3;

result: 600

 

[padana]

But for the expression I can't access the table in a table: 

$expression2 = [
    "type" => "add",
    'children' => [
        [
            "type" => "number",
            "value" => 100
        ],
        [
            "type" => "multiply",
            "children" => [
                [
                    "type" => "number",
                    "value" => 2
                ],
                [
                    "type" => "add",
                    "children" => [
                        [
                            "type" => "number",
                            "value" => 5
                        ],
                        [
                            "type" => "number",
                            "value" => 45
                        ]
                    ]
                ]
            ]
        ]
    ]
];

 

[ginerjm]

You have a different type of array in #2.  Have to modify your code to be more flexible.  Good luck.  I haven't the time to do your homework for you.

[Barand]

$expression2 = [
    "type" => "add",
    'children' => [
        [
            "type" => "number",
            "value" => 100                                     // $expression2['children'][0]['value']
        ],
        [
            "type" => "multiply",
            "children" => [
                [
                    "type" => "number",
                    "value" => 2                              // $expression2['children'][1]['children'][0]['value']
                ],
                [
                    "type" => "add",
                    "children" => [
                        [
                            "type" => "number",
                            "value" => 5                      // $expression2['children'][1]['children'][1]['children'][0]['value']
                        ],
                        [
                            "type" => "number",
                            "value" => 45                     // $expression2['children'][1]['children'][1]['children'][1]['value']
                        ]
                    ]
                ]
            ]
        ]
    ]
];

It's easier if you do a print_r() of the array so you see all the indexes

echo '<pre>$expression2 = ' . print_r($expression2, 1) . '</pre>';

then follow the indexes down the tree ....

showing the path for

echo $expression2['children'][1]['children'][1]['children'][1]['value'];                   // 45