比较未以数字格式列出的JSON API中的数据

Question

PHP beginner here. I want to display compared Data ($myCoins) from a JSON API, so that only those Items will be displayed that I first inserted into the $myCoins arrays, but I can't figure out how to get the code to operate the same with NAMES instead of NUMBERS.

Used API:

https://min-api.cryptocompare.com/data/pricemultifull?fsyms=BTC,ETH,XRB,MIOTA,XRP,XLM,TRX&tsyms=USD

CODE:

<?php
//// API
$coinData = json_decode(file_get_contents('https://min-api.cryptocompare.com/data/pricemultifull?fsyms=BTC,ETH,XRB,IOTA,XRP,XLM,TRX,LINK&tsyms=USD'), true); 

// Arrays
$myCoins = array(
   'BTC' => array ( 'balance' => 12.90 ),
   'ETH' => array ( 'balance' => 122.23 ),
   'XRB' => array ( 'balance' => 221.52 ),
   'MIOTA' => array ('balance' => 233.00 ),
   'XRP' => array ( 'balance' => 429.00 ),
   'XLM' => array ( 'balance' => 1205.89 ),
   'TRX' => array ( 'balance' => 5299.40 )
);

// Fetch the Coins
$numCoins = sizeof ($coinData['RAW']);
$portfolioValue = 0;
for ( $xx=0; $xx<$numCoins; $xx++) {
   // Comparing to Data
   $thisCoinSymbol = $coinData[$xx]['FROMSYMBOL'];
   // 
   $coinHeld = array_key_exists($thisCoinSymbol, $myCoins);
   // Only retour held
    if ( !$coinHeld ) { continue; }

      // names test:
      echo $coinData[$xx]['FROMSYMBOL'];
};
?>

The Tutorial I used was made with an API that displays the Items as numbers, not the Item names like in the API I want to use.

Tutorial API:

https://api.coinmarketcap.com/v1/ticker/

So my console puts out a Undefined offset: 0 - Undefined offset: 7 on line $thisCoinSymbol = $coinData[$xx]['FROMSYMBOL']; I understand that this is because $xx equals 0 - 7, because there are 8 Items under ['RAW'], and there is no 0-7 in the API I use.

How would i get the same result as the Tutorial but with the API I want to use?

Answer 1

You should use a foreach to parse your json that is structured like that:

RAW: {
  BTC: {
    USD: {
      TYPE: "5",
      MARKET: "CCCAGG",
      FROMSYMBOL: "BTC", 
      ....
    }
  },
  ETH: {....},
  ...
}

So your code should looks like that:

<?php

 $coinData = json_decode(file_get_contents('https://min-api.cryptocompare.com/data/pricemultifull?fsyms=BTC,ETH,XRB,IOTA,XRP,XLM,TRX,LINK&tsyms=USD'), true);

 $myCoins = array(
  'BTC' => array ( 'balance' => 12.90 ),
  'ETH' => array ( 'balance' => 122.23 ),
  'XRB' => array ( 'balance' => 221.52 ),
  'MIOTA' => array ('balance' => 233.00 ),
  'XRP' => array ( 'balance' => 429.00 ),
  'XLM' => array ( 'balance' => 1205.89 ),
  'TRX' => array ( 'balance' => 5299.40 )
);

$portfolioValue = 0;

// your information in json path ['RAW'] so safeguard here to be sure it exists
if (isset($coinData['RAW'])) {
  // then loop on all entries $cryptoSymbol will contains for example BTC and cryptoInfo the array USD => [...]
  foreach($coinData['RAW'] as $cryptoSymbol => $cryptoInfo) {
     // safeguard, check path [USD][FROMSYMBOL] exists
     if (!isset($cryptoInfo['USD']) || !isset($cryptoInfo['USD']['FROMSYMBOL'])) {
        // log or do whatever to handle error here
        echo "no path [USD][FROMSYMBOL] found for crypto: " . $cryptoSymbol . PHP_EOL;
        continue;
     }

     // Your symbol in on your json path/array [USD][FROMSYMBOL]
     $thisCoinSymbol = $cryptoInfo['USD']['FROMSYMBOL'];
     $coinHeld = array_key_exists($thisCoinSymbol, $myCoins);
     // Only retour held
     if ( !$coinHeld ) { continue; }

     echo $cryptoInfo['USD']['FROMSYMBOL'] . PHP_EOL;
 }
}
?>

You will have the output:

BTC ETH XRB XRP XLM TRX

Now you can parse the json in the right way, it should be easy for you to build the expected json.

Have a look at the foreach doc here: https://www.php.net/manual/en/control-structures.foreach.php