php – Add "name" in a JSON object

Question:

My JSON currently returns this code below:

{"2":"aluno","8":"barbara_cristina","13":"carolina_deus"}

Is there any way I can add a "header" in the places of numbers 2, 8 and 13? I wanted it to be like this:

{"nome":"aluno","nome":"barbara_cristina","nome":"carolina_deus"}

These are the commands I use to generate the JSON.

$aluno = array();    
while($row = mysqli_fetch_array($verifica))
{ 
   $aluno[]= $row['username'];
} 

$alunoToledo = array(); 
while($lista2 = mysqli_fetch_array($verifica2))
{  
   $alunoToledo[] = $lista2['username'];
}

$result = array_diff($aluno,$alunoToledo);
json_encode($result)

Can anyone help me if this is possible?

Answer:

To do this, just add the keys:

$aluno = array();    
while($row = mysqli_fetch_array($verifica))
{ 
$aluno[]= $row['username'];
} 

$alunoToledo = array(); 
while($lista2 = mysqli_fetch_array($verifica2))
{  
$alunoToledo[] = $lista2['username'];
}

$results = array_diff($aluno,$alunoToledo);
echo '{nome:' . $results[0] . ',nome:' . $results[1] . ',nome:' . $results[2] . '}';

However, the use of JSON is not valid this way, because when using JSON, you must have a key for each one, it would be something similar to this:

[{nome: "nome1"},{nome: "nome2"},{nome: "nome3"},{nome: "nome4"}]

And so, you should do it like this:

$collection = array();
foreach ($results as $result){
    $collection[]['nome'] = $result;  
}

echo json_encode($collection);