PHP遍历JSON数组获取所有txID失败，寻求解决方法

我没法遍历JSON里的所有对象来获取txID，只能指定具体索引逐个获取，想批量打印每个对象的txID，但当前代码没有任何输出。试过Stack Overflow上《Parsing JSON array with PHP foreach》的方案，没用。

我的JSON数据 #

{"data":[{"ret":[{"contractRet":"SUCCESS","fee":0}],"signature":["59ebd5e92c05638d39ddea273cab2b6caf6fcd2e32c790699fa620ab5dcd70496bcd9b73a66c5299e1375b3ea87676dfd0efb7c8914d2f7f9696c8e9ba0c5fe000"],"txID":"b7db5efabb829c19ecffb642e726212e7c06ad5b44bd2c0324a525ed4991923a","net_usage":329,"raw_data_hex":"0a026b1222087c93c9355444acf940b1f08fc1e72f522d53707265616420756e636f6e646974696f6e616c206c6f76652c206d616b65206120686170707920776f726c645a76080212720a32747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e5472616e736665724173736574436f6e7472616374123c0a07313030343033311215419a098706852100c5beeb5054a36a8bdd808a99781a15419b3c8777809cefab5c6116af884af6b2d674be7220c8fb830470d19b8cc1e72f","net_fee":0,"energy_usage":0,"blockNumber":37382949,"block_timestamp":1642693071000,"energy_fee":0,"energy_usage_total":0,"raw_data":{"data":"53707265616420756e636f6e646974696f6e616c206c6f76652c206d616b65206120686170707920776f726c64","contract":[{"parameter":{"value":{"amount":8453576,"asset_name":"1004031","owner_address":"419a098706852100c5beeb5054a36a8bdd808a9978","to_address":"419b3c8777809cefab5c6116af884af6b2d674be72"},"type_url":"type.googleapis.com/protocol.TransferAssetContract"},"type":"TransferAssetContract"}],"ref_block_bytes":"6b12","ref_block_hash":"7c93c9355444acf9","expiration":1642693130289,"timestamp":1642693070289},"internal_transactions":[]},{"ret":[{"contractRet":"SUCCESS","fee":268000}],"signature":["c2e6f20a7786bcbb1867c0c6d8beaccd311b5a5c962a09b5f725b4a04f28e69b663cd87575b96f882c1180cd322e34259ee75849686e9b6348a29809b4aa7d7b01"],"txID":"c3c9ac55378a212f81f3b242b836fcd2a2376c43f8449da8a4787895dcd6d637","net_usage":0,"raw_data_hex":"0a0231952208577691a0d4aab94b40e0f2d7e4dd2f5a68080112640a2d747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e5472616e73666572436f6e747261637412330a15410bc6c882e8cc55c70fd4abae47ad504c48d6e3951215419b3c8777809cefab5c6116af884af6b2d674be721880dac40970cfb0d4e4dd2f","net_fee":268000,"energy_usage":0,"blockNumber":36516246,"block_timestamp":1640083299000,"energy_fee":0,"energy_usage_total":0,"raw_data":{"contract":[{"parameter":{"value":{"amount":20000000,"owner_address":"410bc6c882e8cc55c70fd4abae47ad504c48d6e395","to_address":"419b3c8777809cefab5c6116af884af6b2d674be72"},"type_url":"type.googleapis.com/protocol.TransferContract"},"type":"TransferContract"}],"ref_block_bytes":"3195","ref_block_hash":"577691a0d4aab94b","expiration":1640083356000,"timestamp":1640083298383},"internal_transactions":[]},{"ret":[{"contractRet":"SUCCESS","fee":0}],"signature":["631b0857da6d80da79702c7d31d8d3f2271f35523c7762231c28deeeda59bd1b17246adaabc1d9ebb717a2c3e25811efb31647d22c786e1651bdc8cb84365ead00"],"txID":"c171d5fc085aac3ebaaa68280a72452f3b1a372cf605ef3f5c593a555b7c8daa","net_usage":436,"raw_data_hex":"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","net_fee":0,"energy_usage":0,"blockNumber":32961442,"block_timestamp":1629369408000,"energy_fee":0,"energy_usage_total":0,"raw_data":{"data":"436f6e67726174756c6174696f6e73206f6e2067657474696e67207468652061697264726f702c2077686963682063616e2062652072656465656d6564206174207569666f2e76697020313050414c203d323033322e3754525828e681ade5969ce88eb7e5be97e7a9bae68a95efbc8ce58fafe59ca87569666f2e76697020313050414c203d323033322e37545258e58591e68da229efbc89","contract":[{"parameter":{"value":{"amount":10223,"asset_name":"1003533","owner_address":"416887baae81f63469cb41fb530f1e3bd30a2e2b32","to_address":"419b3c8777809cefab5c6116af884af6b2d674be72"},"type_url":"type.googleapis.com/protocol.TransferAssetContract"},"type":"TransferAssetContract"}],"ref_block_bytes":"f38e","ref_block_hash":"16e44bdfd96d9c3e","expiration":1629369464648,"timestamp":1629369404648},"internal_transactions":[]}],"success":true,"meta":{"at":1660233100523,"fingerprint":"T6atjwJFD2dfCrd8tGpJettk5B1t17FyRLgPs4qgZubyM9WMhKJAkgaTPnUHToWRX9PoBwkLV6Cmrkp1b3noGyVc3C2rRd","links":{"next":"https://api.trongrid.io/v1/accounts/TQ82FS4og14am8BXqndHX8HrYYARrhmjBk/transactions?limit=3&only_confirmed=true&only_to=true&fingerprint=T6atjwJFD2dfCrd8tGpJettk5B1t17FyRLgPs4qgZubyM9WMhKJAkgaTPnUHToWRX9PoBwkLV6Cmrkp1b3noGyVc3C2rRd"},"page_size":3}}

原PHP代码 #

$url = 'https://api.trongrid.io/v1/accounts/TQ82FS4og14am8BXqndHX8HrYYARrhmjBk/transactions?only_confirmed=true&only_to=true&limit=3';

$content = file_get_contents($url);
$array = json_decode($content, true);

foreach ($array as $value) {
    
   echo $value{txID};
}

错误的尝试（仅能指定索引获取） #

foreach ($array as $value) {
        
       echo $value[0]{txID};
    }

解决方案 #

问题核心是JSON结构识别错误：返回的外层数组包含data、success、meta三个键，所有交易对象都嵌套在data字段对应的数组里。你之前直接遍历外层数组，相当于遍历这三个键，自然拿不到txID。

正确的代码应该先定位到$array['data']，再遍历这个数组里的每个交易对象：

$url = 'https://api.trongrid.io/v1/accounts/TQ82FS4og14am8BXqndHX8HrYYARrhmjBk/transactions?only_confirmed=true&only_to=true&limit=3';

$content = file_get_contents($url);
$array = json_decode($content, true);

// 先校验data字段存在且为数组，避免报错
if (isset($array['data']) && is_array($array['data'])) {
    foreach ($array['data'] as $transaction) {
        // 校验txID存在，防止数据异常
        if (isset($transaction['txID'])) {
            echo $transaction['txID'] . PHP_EOL;
        }
    }
}

说明 #

• 直接访问$array['data']拿到包含所有交易的数组，每个元素就是带txID的交易对象。
• 加入isset判断是为了兼容API返回结构变化或数据缺失的情况，避免PHP警告。
• 之前的错误写法中，$value{txID}的语法也不规范，PHP中数组元素应该用$value['txID']的方括号写法。

内容的提问来源于stack exchange，提问作者Dorbagna