PHP create an array with values that equal true - php

Question

I have passed a series of parameters from a jQuery file to a PHP script for processing.
Some of the parameters include names, email, department, etc. The majority of the parameters will either be TRUE or FALSE.
I want to build an array to include all of the parameters that equal TRUE.
<?php
$value = $_POST['criteria'];
$firstname = $value['firstname'];
$email = $value['email'];
$department = $value['department'];
$parameter1 = $value['parameter1']; // equals TRUE
$parameter2 = $value['parameter2']; // equals FALSE
$parameter3 = $value['parameter3']; // equals TRUE
$parameter4 = $value['parameter4']; // equals TRUE
?>
So the results of the array I want to produce should look like this:
$array = ['parameter1', 'parameter3', 'parameter4'];
I know I must use a loop, but I am not exactly sure how to start it.
Edit
Here is where I create the variable criteria in jQuery, starting with a button click event:
$('#requestAppSubmit').on('click', function()
{
var criteria =
{
firstname: $('#firstname').val(),
email: $('#email').val(),
department: $('#department').val(),
// the next parameters check if a checkbox was checked
parameter1: $('#dashboard').is(':checked'),
parameter2: $('#schedules').is(':checked'),
parameter3: $('#finance').is(':checked'),
parameter4: $('#businessplan').is(':checked'),
// quite a few more parameters
}
// then I use a ajax post
$.post('process/editRep.php', {criteria:criteria}, function(data)
{
console.log(data);
//
});
});
At this point, using your suggestions below, the most I can output is this:
Array()

Answer 1

You can use array_filter() to keep only boolean values, and then, use array_keys() to get the names:
$value = [
'firstname'=>'foo',
'email'=>'bar',
'department'=>'baz',
'parameter1'=>true,
'parameter2'=>false,
'parameter3'=>true,
'parameter4'=>true
];
$array = array_filter($value, function($item) {
return $item === true;
});
$array = array_keys($array);
print_r($array);
Output:
Array
(
[0] => parameter1
[1] => parameter3
[2] => parameter4
)
If values are not booleans, you could also use :
$array = array_filter($value, function($item) {
return is_numeric($item) && $item == true;
});
This will work with '0' and '1'.

Answer 2

You don't need a loop at all, just two functions: array_filter to filter out the false values, and array_keys to get the keys:
$array = array_keys(array_filter($values));
// results = ['parameter1', 'parameter3', 'parameter4']

Answer 3

Using foreach:
foreach($value as $index => $bool){
if($bool){
$new_array[] = $index;
}
}
Will only work if your values are of bool type and not string
If they are strings just compare them using ==

Answer 4

I can guess from your question that you need to process a list of parameters you care what their contents are like name, department and email, as well as a boolean list of attributes, in the same POST request.
I would encapsulate all the boolean attributes you need to pass in an array:
<input type="checkbox" name="options[parameter1]"/>
<input type="checkbox" name="options[parameter2]"/>
...
and process it in PHP:
<?php
$options = $_POST['options'] ?? [];
$onlyTrueOptions = array();
foreach($options as $optionName => $value) {
if($value) // or another desidered comparison
$onlyTrueOptions[] = $optionName;
}

Answer 5

Never, really never use "static-incremented" variables. That's what you use arrays for.
$arr = array();
for($i = 1; $i<=4; $i++)
{
if(strcmp($value['parameter'.$i],"TRUE") === 0)
{
array_push($arr,"parameter$i");
}
}