foreach() skipping first element in array - php

Question

Trying to create a GPA Calculator. I have a form that submits to a php file and then stores all data from the form in a php array(). The calculator works great until I enter the same value. I think this wont make sense until I show some pictures:
Here is the problem in an image:
So in the first image I enter a A and then another A which outputs array(1) { [0]=> float(4.5) } when using var_dump()
And in the second image the var_dump() is array(2) { [0]=> float(4) 1=> float(3.5) }
It is skipping the first row in the first image... just in case A is supposed to equal 4.0 in REG and 4.5 in HONORS. It might be the array_combine()
Here is my php code:
//$_POST['grades'] for the grades <option> and $_POST['types'] for the type (REG, HONORS)
foreach(array_combine($_POST['grades'], $_POST['types']) as $code => $count)
{
if ($code == "A")
{
if ($count == "REGULAR")
{
$GradeArray[] = 4.0;
}
else if ($count == "HONORS")
{
$GradeArray[] = 4.5;
}
else if ($count == "COLLEGE")
{
$GradeArray[] = 5.0;
}
}
else if ($code == "B")
{
if ($count == "REGULAR")
{
$GradeArray[] = 3.0;
}
else if ($count == "HONORS")
{
$GradeArray[] = 3.5;
}
else if ($count == "COLLEGE")
{
$GradeArray[] = 4.0;
}
}
else if ($code == "C")
{
if ($count == "REGULAR")
{
$GradeArray[] = 2.0;
}
else if ($count == "HONORS")
{
$GradeArray[] = 2.5;
}
else if ($count == "COLLEGE")
{
$GradeArray[] = 3.0;
}
}
else if ($code == "D")
{
if ($count == "REGULAR")
{
$GradeArray[] = 1.0;
}
else if ($count == "HONORS")
{
$GradeArray[] = 1.5;
}
else if ($count == "COLLEGE")
{
$GradeArray[] = 2.0;
}
}
else if ($code == "F")
{
if ($count == "REGULAR")
{
$GradeArray[] = 0.0;
}
else if ($count == "HONORS")
{
$GradeArray[] = .5;
}
else if ($count == "COLLEGE")
{
$GradeArray[] = 1.0;
}
}
}
It might be the whole foreach() statement that needs reworking... I am up to writing the logic again if anyone says so...
I don't want to clog up the question with code so if you absolutely need the html just ask and I will add in an edit.
EDIT: I am also thinking I need to rewrite the logic... I have never used array_combine() before... I just need to make sure the corresponds with the related
Thanks for the help!

Answer 1

If you want to iterate over two arrays (or more) you could consider using the MultipleIterator; it doesn't clobber array keys like array_combine() does.
You could also simplify your logic by using an array to define the scores of each grade / type combination:
$gradesToScores = array(
'REGULAR' => array(
'A' => 4.0, 'B' => 3.0, 'C' => 2.0, 'D' => 1.0, 'F' => 0.0,
),
'HONORS' => array(
'A' => 4.5, 'B' => 3.5, 'C' => 2.5, 'D' => 1.5, 'F' => 0.5,
),
'COLLEGE' => array(
'A' => 5.0, 'B' => 4.0, 'C' => 3.0, 'D' => 2.0, 'F' => 1.0,
),
);
$gradeItemIterator = new MultipleIterator(MultipleIterator::MIT_KEYS_ASSOC);
$gradeItemIterator->attachIterator(new ArrayIterator($_POST['grades']), 'grade');
$gradeItemIterator->attachIterator(new ArrayIterator($_POST['types']), 'type');
$gradeScores = array();
foreach ($gradeItemIterator as $gradeItem) {
$gradeScores[] = $gradesToScores[$gradeItem['type']][$gradeItem['grade']];
}

Answer 2

look at this array and output look the VALUES "a" which becomes the key of the resultant array,
so if u want the full array to be combined with the key of first array then first array must kave unique values.
<?php
print_r(array_combine(Array('a','a','b'), Array(1,2,3)));
?>
Returns:
Array
(
[a] => 2
[b] => 3
)
solution (may not be the best )
foreach($_POST['grades'] as $KEY=>$code)
{
$count = $_POST['types'][$KEY];
if ($code == "A")
{
if ($count == "REGULAR")
{
$GradeArray[] = 4.0;
}
else if ($count == "HONORS")
{
$GradeArray[] = 4.5;
}
else if ($count == "COLLEGE")
{
$GradeArray[] = 5.0;
}
}
else if ($code == "B")
{
if ($count == "REGULAR")
{
$GradeArray[] = 3.0;
}
else if ($count == "HONORS")
{
$GradeArray[] = 3.5;
}
else if ($count == "COLLEGE")
{
$GradeArray[] = 4.0;
}
}
else if ($code == "C")
{
if ($count == "REGULAR")
{
$GradeArray[] = 2.0;
}
else if ($count == "HONORS")
{
$GradeArray[] = 2.5;
}
else if ($count == "COLLEGE")
{
$GradeArray[] = 3.0;
}
}
else if ($code == "D")
{
if ($count == "REGULAR")
{
$GradeArray[] = 1.0;
}
else if ($count == "HONORS")
{
$GradeArray[] = 1.5;
}
else if ($count == "COLLEGE")
{
$GradeArray[] = 2.0;
}
}
else if ($code == "F")
{
if ($count == "REGULAR")
{
$GradeArray[] = 0.0;
}
else if ($count == "HONORS")
{
$GradeArray[] = .5;
}
else if ($count == "COLLEGE")
{
$GradeArray[] = 1.0;
}
}
}

Answer 3

I agree with Arun on the reason for the behaviour. A possible solution would be:
$lookup = Array("A"=>4, "B"=>3, "C"=>2, "D"=>1, "F"=>0);
for ( $i=0; $i<count($_POST['grades']); $i++ ) {
$temp = $lookup[ $_POST['grades'][$i] ];
if ( $_POST['types'][$i] == "HONORS" ) {
$temp += .5;
}
elseif ( $_POST['types'][$i] == "COLLEGE" ) {
$temp += 1;
}
$GradeArray[] = $temp;
}
This assumes the count of $_POST['grades'] and $_POST['types'] to be equal - otherwise it will either cause an undefined offset notice or not address each value.
Regarding Arun's code: nesting the two loops will create N*M inner loop iterations - one for each combination of grade/type, clearly wrong in this case! We need to go through the arrays in parallel, as they are used to hold pair values.
#Jack: If I'm not mistaken, you need to swap HONORS and COLLEGE in your Array definition.

Answer 4

This solution works for me fine
$array = array('ab', 'bc', 'cd', 'de');
$array = array_combine(range(1, count($array)), array_values($array));
print_r($array);