Increment in fetch array while loop - php

Question

I have trouble to increment correctly a variable in a while loop where I fetch data from my database.
This is the code:
while ($row = $result->fetch_array(MYSQLI_ASSOC)) {
//January
if ($row['month'] ==1){
if ($row['day_range'] == '01-07') {
$val1_1 = $row['duration'];
$int1_1 = $row['intensity'];
}
elseif ($row['day_range'] == '08-14') {
$val1_2 = $row['duration'];
$int1_2 = $row['intensity'];
}
elseif ($row['day_range'] == '15-21') {
$val1_3 = $row['duration'];
$int1_3 = $row['intensity'];
}
elseif ($row['day_range'] == '22-end') {
$val1_4 = $row['duration'];
$int1_4 = $row['intensity'];
}
//Avg intensity
$int1 = ($int1_1 + $int1_2 + $int1_3 + $int1_4)/4;
}
}
So I have this code for every month.
The problem here is that sometimes I don't have 4 values, so at the end when I calculate the AVG it is sometimes wrong because it always divides it by 4
What I've done :
I had the idea of incrementing a variable $i each time I have a value, like this
$i = 0;
while ($row = $result->fetch_array(MYSQLI_ASSOC)) {
//January
if ($row['month'] ==1) {
if ($row['day_range'] == '01-07') {
$val1_1 = $row['duration'];
$int1_1 = $row['intensity'];
$i++;
}
elseif ($row['day_range'] == '08-14') {
$val1_2 = $row['duration'];
$int1_2 = $row['intensity'];
$i++;
}
elseif ($row['day_range'] == '15-21') {
$val1_3 = $row['duration'];
$int1_3 = $row['intensity'];
$i++;
}
elseif ($row['day_range'] == '22-end') {
$val1_4 = $row['duration'];
$int1_4 = $row['intensity'];
$i++;
}
//Avg intensity
$int1 = ($int1_1 + $int1_2 + $int1_3 + $int1_4)/$i;
}
$i = 0;
//code for next month
}
But it doesn't work, I've echoed it and $i stays at 1.
I think it is because it fetch row by row so it never goes through all incrementations to reach the value desired.
How can I do that please?

Answer 1

// Here is an array to get the data of EACH month
$month = array();
$i = 0;
while ($row = $result->fetch_array(MYSQLI_ASSOC)) {
// This way, you will have $month[1] for January, $month[2] for February, etc.
$month[$row['month']][] = array(
"duration" => $row['duration'],
"intensity" => $row['intensity'];
);
}
// Now you get all the data, you can calculate the Avg intensity for each month
foreach ($month as $month_number => $data) {
$moy = count($month[$month_number]); // Will be 4 if you have 4 period, 3 if only 3, etc.
$sum = 0;
foreach ($data as $value) {
$sum += $value['intensity'];
}
$month[$month_number]['avg_intensity'] = $sum / $moy;
}
With this method you should get an array with all the data you want that look like this :
$month = array(
// January
1 => array(
0 => array(
'duration' => ...,
'intensity' => ...
),
1 => array(
'duration' => ...,
'intensity' => ...
),
...
'avg_intensity' => /* moy of all intensity of the month */
),
// February
2 => array(
...
),
...
);
Hope it helps you !
EDIT :
As suggested if the comment by Nigel Ren, you can replace
$sum = 0;
foreach ($data as $value) {
$sum += $value['intensity'];
}
By
$sum = array_sum(array_column($data, "intensity"));

Answer 2

Please try like
$int1_1 += $row['intensity'];
way.
That means
$i = 0;
$int1_1 = 0;
while ($row = $result->fetch_array(MYSQLI_ASSOC)) {
//January
if($row['month'] ==1){
if($row['day_range'] == '01-07'){
$val1_1 = $row['duration'];
$int1_1 += $row['intensity'];
$i++;
}
elseif($row['day_range'] == '08-14'){
$val1_2 = $row['duration'];
$int1_1 += $row['intensity'];
$i++;
}
elseif($row['day_range'] == '15-21'){
$val1_3 = $row['duration'];
$int1_1 += = $row['intensity'];
$i++;
}
elseif($row['day_range'] == '22-end'){
$val1_4 = $row['duration'];
$int1_1 += $row['intensity'];
$i++;
}
//Avg intensity
$int1 = $int1_1/$i;
}
$i=0;
//code for next month
}