I have the following JSON:
[{
"units": "06-019",
"duration_1": "4.96",
"custom0": "",
"absolute_mileage_end_0": "31694 km",
"duration_0": "18.02",
"duration_stay_0": "7.33",
"mileage_0": "261 km"
},
{
"units": "06-021",
"duration_1": "6.26",
"custom0": "",
"absolute_mileage_end_0": "91380 km",
"duration_0": "21.10",
"duration_stay_0": "7.66",
"mileage_0": "603 km"
},
{
"units": "06-287",
"duration_1": "10.61",
"custom0": "",
"absolute_mileage_end_0": "119741 km",
"duration_0": "26.67",
"duration_stay_0": "11.53",
"mileage_0": "541 km"
},
{
"units": "06-289",
"duration_1": "2.44",
"custom0": "",
"absolute_mileage_end_0": "89425 km",
**"duration_0": "7.78",**
"duration_stay_0": "2.98",
"mileage_0": "169 km"
}]
I will capture the the following formula
$formula= "duration_0-duration_1";
how can I calculate the result based on the formula for each element in the array in PHP using the eval() function?
Decode the JSON and loop it. Then in the formula, replace the array keys with the values using strtr and eval it:
$formula = "duration_0-duration_1";
$array = json_decode($json, true);
foreach($array as $values) {
$calc = strtr($formula, $values);
eval("echo $calc . PHP_EOL;");
// or
eval("\$result = $calc;");
}