parsing json file in php trouble

Question

i have this data cennik.json file:

{
    "waluta": "PLN",
    "vat": 1.23,
    "00101": {
        "cena": 340,
        "powiazanyZ": "00139"
    },
    "00102": {
        "cena": 325.33,
        "powiazanyZ": "00140"
    },
    "00103": {
        "cena": 306.67,
        "powiazanyZ": "00141"
    },
    "00104": {
        "cena": 289.33,
        "powiazanyZ": "00142"
    },
    "00105": {
        "cena": 276,
        "powiazanyZ": "00143"
    },
    "00106": {
        "cena": 258.67,
        "powiazanyZ": "00144"
    },
    "00107": {
        "cena": 240,
        "powiazanyZ": "00145"
    },
    "00108": {
        "cena": 222.67,
        "powiazanyZ": "00146"
    },
    "00109": {
        "cena": 205.33,
        "powiazanyZ": "00147"
    },
    "00110": {
        "cena": 189.33,
        "powiazanyZ": "00148"
    },
    "00120": {
        "cena": 413.33,
        "powiazanyZ": "00150"
    },
    "00121": {
        "cena": 73.33,
        "powiazanyZ": "00000"
    },
    "00122": {
        "cena": 153.33,
        "powiazanyZ": "00000"
    },
    "00123": {
        "cena": 153.33,
        "powiazanyZ": "00000"
    },
    "00138": {
        "cena": 1937,
        "powiazanyZ": "00152"
    },
    "00139": {
        "cena": 366.82,
        "powiazanyZ": "00101"
    },
    "00140": {
        "cena": 325.33,
        "powiazanyZ": "00102"
    },
    "00141": {
        "cena": 306.67,
        "powiazanyZ": "00103"
    },
    "00142": {
        "cena": 289.33,
        "powiazanyZ": "001041"
    },
    "00143": {
        "cena": 276,
        "powiazanyZ": "00105"
    },
    "00144": {
        "cena": 258.67,
        "powiazanyZ": "00106"
    },
    "00145": {
        "cena": 240,
        "powiazanyZ": "00107"
    },
    "00146": {
        "cena": 222.67,
        "powiazanyZ": "00108"
    },
    "00147": {
        "cena": 205.33,
        "powiazanyZ": "00109"
    },
    "00148": {
        "cena": 189.33,
        "powiazanyZ": "00110"
    },
    "00150": {
        "cena": 413.33,
        "powiazanyZ": "00120"
    },
    "00152": {
        "cena": 1997.33,
        "powiazanyZ": "00138"
    }
}

and this from my php file:

$vat = 0.00;
$waluta = '';
$kod00101 = 0.00;
$kod00102 = 0.00;
...
$kod00152 = 0.00;

$cennik_plik = file_get_contents("cennik.json");
$jsonIterator = new RecursiveIteratorIterator(
    new RecursiveArrayIterator(json_decode($cennik_plik, TRUE)),
    RecursiveIteratorIterator::SELF_FIRST);

foreach ($jsonIterator as $key => $val) {
    if(is_array($val)) {
        $v = ${'kod'.$key};
        if('$key' == $v){
            $v = number_format((float)$val[cena],2,'.','');
        }
    } else {
        if('$key' == 'waluta') {$waluta = $val;};
        if('$key' == 'vat') {$vat = number_format((float)$val,2,'.','');};
    }
}

i am trying this and i get following error:

Fatal error: Uncaught exception 'InvalidArgumentException' with message 'Passed variable is not an array or object, using empty array instead' in C:\Documents and Settings\user\Desktop\Lighty2Go\HTDOCS\ogr\index.php:50
Stack trace:
 #0 C:\Documents and Settings\user\Desktop\Lighty2Go\HTDOCS\ogr\index.php(50): ArrayIterator->__construct('???{?? "walu...')
 #1 {main} thrown in C:\Documents and Settings\user\Desktop\Lighty2Go\HTDOCS\ogr\index.php on line 50

Any Suggestions?

I have tried to solve it myself using these resources, but nothing:

• Parsing JSON file with PHP
• Parsing this JSON file structure

Answer 1

I'm not quite sure what you are attempting with that data. But you certainly don't need that RecursiveArrayIterator. A boring foreach is enough to traverse that array:

$json = file_get_contents("cennik.json");
# the culprit was the UTF-8 BOM, which OPs specific verison of json_decode tripped over (newer versions would return NULL)
$json = preg_replace('/^\xEF\xBB\xBF/', '', $json);
$array = json_decode($json, TRUE);

var_dump($array);    # <-- WHAT DOES THAT OUTPUT ??


foreach ($array as $key => $value) {

    if ($key == "waluta") {
        $waluta = $value;
    }
    elseif ($key == "vat") {
        $vat = $value;
    }

    // all the data entries
    elseif (is_numeric($key)) {
        $kod[$key] = $value["cena"];
        // ${"kod$key"} = ...;
    }
}

Note that you can use variable variables. But this example screams array. I'm not even sure why you would want to use a separate list of variables. The source array should be good enough to work with.