Streamlining POST checks

[julianbrezon]

I have a random exercise picker which allows the user to "okay" various choices which my script then picks from. It works fine and what I'm here to inquire about is if there's any way I can shorten the code. I imagine there's something I could do with the array_push sections since it's so repetitive.

If you want to see what the script is doing, it's at my site:

http://www.julianbrezon.com/exercises.php

<?php
/* Theory: 
Check to see if each key, individually is true. 
If it is true, array_push it's value into the $keys array.
Count the number of objects in that array.
Use the random picker but use the number of items instead of 12. 
*/
//----------
//
//Create key array
$key = array();
//Check to see if box is checked. If it is checked, add it to the array:
if ($_POST["c"] == "true"){
array_push($key, "C");
}
else {}
if ($_POST["f"] == "true"){
array_push($key, "F");
}
else {}
if ($_POST["bb"] == "true"){
array_push($key, "Bb");
}
else {}
if ($_POST["eb"] == "true"){
array_push($key, "Eb");
}
else {}
if ($_POST["ab"] == "true"){
array_push($key, "Ab");
}
else {}
if ($_POST["c#"] == "true"){
array_push($key, "C#");
}
else {}
if ($_POST["f#"] == "true"){
array_push($key, "F#");
}
else {}
if ($_POST["b"] == "true"){
array_push($key, "B");
}
else {}
if ($_POST["e"] == "true"){
array_push($key, "E");
}
else {}
if ($_POST["a"] == "true"){
array_push($key, "A");
}
else {}
if ($_POST["d"] == "true"){
array_push($key, "D");
}
else {}
if ($_POST["g"] == "true"){
array_push($key, "G");
}
else {}
//iterations 
$iterations = $_POST["iterations"];
//Count the number of objects in the array 
$howmanykeys = count($key);
//How many iterations?
for ($i=0; $i < $iterations; $i++){
// Choose the exercise
$exercise=array("Zero",""Up a Chord"",""Up a Chord, Down a Scale"",""Up a Chord Down a Chord"",""Winding"",""Up a Triad"",""Half Step to Triads"",""Third of Triad Up"",""Third of Triad Down"");
$whatex = (mt_rand()%8+1);
$whatkey = (mt_rand(0, $howmanykeys - 1));
// Print the exercises!!
echo "Perform the " . $exercise[$whatex] . " exercise in the key of " . $key[$whatkey] . "<br />";
sleep(.5);
}	
?>

[premiso]

$checkBoxes = array("c", "f", "bb"); // etc
foreach ($checkBoxes as $key) {
    if (isset($_POST[$key]) && $_POST[$key] == "true") {
        array_push($key, ucwords($key));
    }
}

// iterations

 

One way to shorten it. You also do not need "else {}" after every if statement. It is not a required piece.