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Accepted
Eduardo Munizaga
Asked: 2020-02-20 05:47:17 +0800 CST 2020-02-20 05:47:17 +0800 CST

How to give the desired format to an associative array of objects to be used in Highcharts charts?

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I am working with Highcharts charts by generating a request jQuery.get()from the chart to the temperature3.php file . For the chart to work properly, the JSON must be in the following format:

[{"item": "minima", "data":[["2015-12-28",8.8],["2015-12-29",10.8],["2015-12-30",15.3]]},
{"item": "maxima", "data":[["2015-12-28",28.7],["2015-12-29",27.5],["2015-12-30",31.1]]}]

The routine (summarized) that I am using to obtain this format is the following:

$minima='{"item": "minima", "data":[';
$maxima='{"item": "maxima", "data":[';

foreach($stm->fetchAll(PDO::FETCH_ASSOC) as $r)
{
    $minima.='["'. $r['fecha'].'",'.$r['minima'].'],';
    $maxima.='["'. $r['fecha'].'",'.$r['maxima'].'],';
}

$minima.=']}';
$maxima.=']}';

$datos = '['.$minima.','.$maxima.']';
$datos= str_replace(",]", "]", $datos); 
echo json_encode($datos,JSON_NUMERIC_CHECK);

The summary table has the following format

id       fecha       maxima  minima  
------  ----------  ------  --------
     1  2015-12-28    28.7       8.8
     2  2015-12-29    27.5      10.8
     3  2015-12-30    31.1      15.3

It is effective but not optimal and less efficient. So I guess there must be some less naive way to do it, either through a multidimensional array of objects or some solution that I haven't been able to see.

php

1 Answers

  1. Best Answer

    One option, as you say, would be to define your own multidimensional objects and arrays. For example:

    class TemperaturasTipo {
    public $item = "";
    public $data = array();

    public function __construct($item) {
        $this->item = $item;
    }

    public function addData($fecha, $valor) {
        array_push($this->data, array($fecha, $valor));
    }
}

class Temperaturas {
    public $minimas;
    public $maximas;

    public function __construct() {
        $this->minimas = new TemperaturasTipo("minima");
        $this->maximas = new TemperaturasTipo("maxima");
    }

    public function insertarMinima($fecha, $valor) {
        $this->minimas->addData($fecha, $valor);
    }

    public function insertarMaxima($fecha, $valor) {
        $this->maximas->addData($fecha, $valor);
    }

    public function __toString() {
        return json_encode(array($this->minimas, $this->maximas));
    }
}

    And with that the code above would be simplified to:

    $temp = new Temperaturas();

foreach($stm->fetchAll(PDO::FETCH_ASSOC) as $r)
{
    $temp->insertarMinima($r['fecha'], $r['minima']);
    $temp->insertarMaxima($r['fecha'], $r['maxima']);
}

echo $temp;
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