循环遍历php中的json对象数组

Question

I have this json a array of object and I want to loop through and display all parents with its child

[
    {
        "ProfessionName": "Technique ",
        "ParentProfessionNum": "",
        "ParentProfession": null,
        "Id": 1,
        "RowVersion": null,
        "RowRevision": null
    },
    {
        "ProfessionName": "Production ",
        "ParentProfessionNum": "1",
        "ParentProfession": null,
        "Id": 2,
        "RowVersion": null,
        "RowRevision": null
    },
    {
        "ProfessionName": "Maintenance ",
        "ParentProfessionNum": "1",
        "ParentProfession": null,
        "Id": 3,
        "RowVersion": null,
        "RowRevision": null
    },
    {
        "ProfessionName": "Maintenance Unit Manager",
        "ParentProfessionNum": "3",
        "ParentProfession": null,
        "Id": 4,
        "RowVersion": null,
        "RowRevision": null
    },
    {
        "ProfessionName": "Maintenance operator",
        "ParentProfessionNum": "3",
        "ParentProfession": null,
        "Id": 5,
        "RowVersion": null,
        "RowRevision": null
    },
    {
        "ProfessionName": "Liquid maintenance operator",
        "ParentProfessionNum": "3",
        "ParentProfession": null,
        "Id": 6,
        "RowVersion": null,
        "RowRevision": null
    },
    {
        "ProfessionName": "Production Unit Manager",
        "ParentProfessionNum": "2",
        "ParentProfession": null,
        "Id": 7,
        "RowVersion": null,
        "RowRevision": null
    },
    {
        "ProfessionName": "project manager",
        "ParentProfessionNum": "2",
        "ParentProfession": null,
        "Id": 8,
        "RowVersion": null,
        "RowRevision": null
    },
    {
        "ProfessionName": "Machine operator",
        "ParentProfessionNum": "2",
        "ParentProfession": null,
        "Id": 9,
        "RowVersion": null,
        "RowRevision": null
    }
]

I did follows first I split parents and child in separate arrays if parent then ParentProfessionNum must be null and if child this should have an ID of another array

$parents = array();
$childs = array();
foreach ($data as $job) {
     if (!$job['ParentProfessionNum']) {
       array_push($parents, $job);
     } else {
       array_push($childs, $job);
       }
     };

then I did a loop using foreach

foreach ($parents as $p) {
   echo $p['ProfessionName'];
   $parent_id = $p['Id'];
   foreach ($childs as $c) {
       if ((int) $c['ParentProfessionNum'] == $parent_id) {
          echo $c['ProfessionName'];
       }
   }
}

but this shows only first parent's child.

Update this is the output Technique (parent) Production (child) Maintenance (child)

but also these child are parent for another child I want to display them all as tree view or any other way

Answer 1

You have never set $parent_id ... use instead $p['id'] or set $parent_id = $p['id']

Also the (int) cast is useless until you use == because PHP will check for equality of value and not type, so 1=="1" is true, instead 1==="1" is false, and so the cast is needed

So the code should be

foreach ($data as $p) {
    echo "PARENT : ".$p->ProfessionName."\n";
    $parent_id = $p->Id;
    echo "CHILDREN : \n";
    foreach ($data as $c) {
        if ($c->ParentProfessionNum == $parent_id) {
            echo $c->ProfessionName."\n";
        }
    }
    echo "\n";
}

Answer 2

inside child for loop

replace if statement's condition from

if ((int) $c['ParentProfessionNum'] == $parent_id) {

with

if ((int) $c['ParentProfessionNum'] == $p['id']) {

after analyzing your array, if objects with ProfessionName "Production" and "Maintenance " are also parents than you should make "ParentProfessionNum" empty or null

"ParentProfessionNum" = ""

instead of

"ParentProfessionNum" = "1"

UPDATE (based on the question update)
with some object being both child and parent at a time,

you need more attributes (let's say is_parent and is_child ) and then separate using child and parent using those attributes so some of the objects wil be on both arrays parent and child

foreach ($data as $job) {
  if ($job['is_parent']) {
    array_push($parents, $job);
  } 
  if ($job['is_child']) {
    array_push($childs, $job);
  }
};

Answer 3

This looks like a logic problem.

The first step should be to get all the parents. Then loop through the array of parents and print all the children for that parent So,

// Get the unique values of parent Ids
$parentsIndex = array_unique(array_column($data, 'ParentProfessionNum'));
sort($parentsIndex);

//Loop through the parents
foreach ($parentsIndex as $key=>$p) {
  // Skip Technique in parent
  if("" != $p) {
    // get the index for the original parent element in $data
    $key = $p-1;

    //always check if index exists 
    if (isset($data[$key]['ProfessionName'])) {
      // Print Parent
      echo $data[$key]['ProfessionName']."\n";
    }

    // Print children
    foreach ($data as $c) {
      //always check if index exists 
      if (isset($c['ParentProfessionNum'])) {
        if ($c['ParentProfessionNum'] == $p  ) {
          echo "   " . $c['ProfessionName']."\n";
        }
      }
    }
  }
}