changing content of multidimensional array in php?

Question

I have a multidimensional array in php, which I want to manipulate according to some rules.

Input-Array: (Variable printed as JSON)

[
    {
        "meta":{
                "title": "Adressdata",
                "name": "adress"
        },    
        "data":{
            "desc":{    "tooltip":  "text",
                        "maxlength":    "100"
                },
            "line1":{   "tooltip":  "Recipient",
                        "maxlength":    "40"
                }
    }
]

Rules:

{
    "0>meta>title": "Companyaddress",
    "0>data>desc": {
        "tooltip": "Another Text",
        "maxLength": "150"
    }
}

(There are 2 rules, the index explains which field from the input-array has to be changed, and the value contains the data to be inserted instead. Note that the second rule wants to insert an object)

Problem:

I want to change the content of the input-array according to the rules, but I struggle in doing that.

Here's the php-Code I already have:

<?php
    $input = json_decode(file_get_contents("inputData.json"),true);
    $rules = json_decode(file_get_contents("rules.json"),true);

    foreach ($rules as $target => $replacement) {       
        //rule:  "0>meta>title": "newTitle"

        $node = $input;
        foreach (explode(">",$target) as $index) {
            $node = $node[$index];
        }

        $node = $replacement;   //replace doesn't work    
    }

    echo "Result-Array: ";
    print_r($input);
?>

Everything works, in except that I can't change the values. Why? Because everytime I set $node-Variable, I create a new Variable. And I only change the content of $node, but not the content of $input.

So I tried to use references - which doesn't work either: When I change the 2 $node-Lines to this code:

$node = &$input;
[...]
$node = &$node[$keys[$i]];  //go to child-node

But this doesn't work, because the second line, where I just want to navigate to a child-node, changes the parent-element (because $node is a reference).

I have no idea if there's a trick to do that, I hope someone can help me

@Smandoli: I have a textfile with the above JSON-content. And I load it with $input = json_decode(file_get_contents("path.json"),true); — maja
– maja, Commented Jul 28, 2013 at 14:54
I can also change the rules so they have another format, but I need to have the same functionality. — maja
– maja, Commented Jul 28, 2013 at 14:58

u_mulder · Accepted Answer · 2013-07-28 16:32:27Z

1

Okay, here's some decision, but you should change $rules structure, it should be the same as $input:

$input = json_decode('[{"meta":{"title": "Adressdata","name": "adress"},"data":{"desc":{"tooltip":"text","maxlength":"100"},"line1":{"tooltip":"Recipient","maxlength":"40"}}}]',true);
$rules = json_decode('[{"meta":{"title": "Companyaddress"},"data":{"desc":{"tooltip":"Another Text","maxlength":"150"}}}]',true);

 // if you print both arrays you will see that they have the similar structure
 // but $rules consists only of items that you need to change.
 // next:
 echo'<pre>',print_r(array_replace_recursive($input, $rules)),'</pre>';

 // BINGO!

answered Jul 28, 2013 at 16:32

u_mulder

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maja Over a year ago

simple and awesome .. I would have never thought about this. There's only one thing which works differently: When I have a rule to replace a node with an object, this solutions may not delete existing content from the input-array. But in my case it's no problem

maja · Accepted Answer · 2013-07-28 16:30:56Z

Ok, after some frustrating hours, I finally found a way to achieve this.

This is the function I wrote:

/**
 * Manipulates an array according to the given rules
 */
function manipulateData($input, $manipulations){

    foreach ($manipulations as $target => $replacement) {   //for each rule 
        $tmpRefNum = 0;                              //Variable-Nameprefix for the reference (don't generate random names)

        $node = "node".(++$tmpRefNum);               //"node1"
        $$node = &$input;                            //$node1 --> $input

        foreach (explode(">",$target) as $index) {   //for each child in the rule           
            $parent = &$$node;                       //We search for a child. So the old node becomes a parent

            if(!isset($parent[$index])){             //Does the child exist?        no --> create missing child             
                $parent[$index] = "";                //give birth! (value will be set later)                
            }

            $node = "node".(++$tmpRefNum);           //Generate a new reference-Name: "node2", "node3", ...
            $$node = &$parent[$index];               //Point to child        
        }

        $$node = $replacement;                       //Change the child-content

        //Unset all generated references (just to not spam the variables)
        /* */   for($i=1;$i<=$tmpRefNum;$i++){
        /* */       $node = "node".$i;
        /* */       unset($$node);
        /* */   }
        /* */   
    }
    return $input;
}

Description:

The solution is, that I just generate a new variable/reference for each child-node I find. In order to do this, I need the $$-Syntax provided by php.

It's a bit dirty, because I have a variable-factory, so if someone finds a better solution it would be awesome.

It would be great, if I would get some feedback if this is a good solution or not.

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