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如何在PHP中解析具有变量和显示最大值的JSON数组中的列？ [重复]

分类: 技术问答 • 2022-03-04 17:28:38

如何在PHP中解析具有变量和显示最大值的JSON数组中的列？ [重复]

问题描述：

This question already has an answer here:

I have a JSON array, I get it from the REST API using curl and I want to get all the numbers from the "c" column and then find the maximum.

function part of my code

curl_setopt($ch, CURLOPT_URL, "https://api-domain.com/v3/instruments/" . $ticker . "/candles?&price=A&from=" . $first . "&to=" . $second . "&granularity=D");
// get stringified data/output. See CURLOPT_RETURNTRANSFER
$data = curl_exec($ch);
// get info about the request
$info = curl_getinfo($ch);
// close curl resource to free up system resources
curl_close($ch);
$json_string = $data;
$jsondata = ($json_string);
$obj = json_decode($jsondata,true);
print_r($jsondata); //below get the answer

//(print_r output)

{
"instrument":"EUR_USD",
"granularity":"D",
"candles":[
{
"complete":true,
"volume":32813,
"time":"2017-01-02T22:00:00.000000000Z",
"ask":{
"o":"1.04711",
"h":"1.04908",
"l":"1.03413",
"c":"1.04061"
}
},
{
"complete":true,
"volume":34501,
"time":"2017-01-03T22:00:00.000000000Z",
"ask":{
"o":"1.04076",
"h":"1.05009",
"l":"1.03907",
"c":"1.04908"
}
},
{
"complete":true,
"volume":52627,
"time":"2017-01-04T22:00:00.000000000Z",
"ask":{
"o":"1.04911",
"h":"1.06161",
"l":"1.04816",
"c":"1.06083"
}}]}

</div>

此问题已经存在 这里有一个答案： p>

  • 从多维数组中的元素中获取最大值？ \ r 4 answers span> li> ul> div>

    我有一个JSON数组， 我使用 curl code>从REST API中获取它，我想从“c” strong>列中获取所有数字，然后找到最大值 strong>。 p>

    我的代码的功能部分 em> strong> p> 

      curl_setopt（$ ch，CURLOPT_URL  ，“https://api-domain.com/v3/instruments/”。$ ticker。“/ candle？＆amp; price = A＆amp; from =”。$ first。“＆amp; to =”。$ second。“＆amp;  ;粒度= d“）; \  n //获取字符串化数据/输出。 请参阅CURLOPT_RETURNTRANSFER 
 $ data = curl_exec（$ ch）; 
 //获取有关请求的信息
 $ info = curl_getinfo（$ ch）; 
 //关闭curl资源以释放系统资源
curl_close（$ ch  ）; 
 $ json_string = $ data; 
 $ jsondata =（$ json_string）; 
 $ obj = json_decode（$ jsondata，true）; 
print_r（$ jsondata）;  //下面得到答案
  code>  pre> 
 
 
     //（  print_r输出 em>  strong>） p> 
 \  ñ
      {
 “个仪器”： “EUR_USD” 
 “个粒度”： “d”，
 “个蜡烛”：[\ N {
 “个完整”：真，
“个体积 “：32813，
” 个时间 “：” 2017-01-02T22：00：00.000000000Z” 
 “个问”：{
 “○”： “1.04711”，
 “H”： “1.04908”，  
 “L”： “1.03413”，
 “C”： “1.04061” \ N} \ N}，\ N {
 “个完整”：真，
 “个体积”：34501，
 “时间”  ： “2017-01-03T22：00：00.000000000Z” 
 “个问”：{
 “○”： “1.04076”，
 “H”： “1.05009”，
 “L”： “1.03907”  ，
 “C”： “1.04908” \ N} \ N}，\ N {
 “个完整”：真，
 “个体积”：52627，
 “个时间”：“2017-01-04T22：00  ：00.000000000Z “
 ”个问“：{
 ”○“： ”1.04911“，
 ”H“： ”1.06161“，
 ”L“： ”1.04816“，
 ”C“：” 1.06083  “
}}]} 
  code>  pre> 
  div>

答

You need to do following to get desired output.

  1. Decode json
  2. Map array
  3. Sort

Snippet

$data = '{
"instrument":"EUR_USD",
"granularity":"D",
"candles":[
{
"complete":true,
"volume":32813,
"time":"2017-01-02T22:00:00.000000000Z",
"ask":{
"o":"1.04711",
"h":"1.04908",
"l":"1.03413",
"c":"1.04061"
}
},
{
"complete":true,
"volume":34501,
"time":"2017-01-03T22:00:00.000000000Z",
"ask":{
"o":"1.04076",
"h":"1.05009",
"l":"1.03907",
"c":"1.04908"
}
},
{
"complete":true,
"volume":52627,
"time":"2017-01-04T22:00:00.000000000Z",
"ask":{
"o":"1.04911",
"h":"1.06161",
"l":"1.04816",
"c":"1.06083"
}}]}';

$arr = json_decode($data,true);

$c = array_map( function ($in){
return  $in['ask']['c'];
}, $arr['candles']);

sort($c);

echo 'Min is: '.current($c)."
";
echo 'Max is: '.end($c);

Output

Min is: 1.04061
Max is: 1.06083

Live demo

Docs

  1. array_map
  2. sort

答

You could build an array of the close prices using array_map() with an anynomous function and then get the highest value using max():

// This will return an array of the close prices
$close_prices = array_map(function ($candle) {
    return $candle['ask']['c'];
},
$jsondata['candles']); // <-- Of course send the candlesticks array

// Now get the highest value in the close prices array
$highest = max($close_prices);


echo 'Maximum EUR/USD value: 1 EUR = ' . $highest . ' USD';
// Maximum EUR/USD value: 1 EUR = 1.06083 USD

Same code, shorter:

$highest = max(array_map(function($c) { return $c['ask']['c']; }, $jsondata['candles']));

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