How to use nested loop in this example? - php

Question

Consider the following $data array:
Array
(
[0] => Array
(
[code] => 20
[name] => Name 1
[month] => 4
[cost] => 100
..
..
)
[1] => Array
(
[code] => 30
[name] => Name 2
[month] => 3
[cost] => 120
..
..
)
[1] => Array
(
[code] => 30
[name] => Name 2
[month] => 6
[cost] => 180
..
..
)
..
..
)
Each array can have unknown number of codes. Each code has a different month ID. I want to sort and display the data so that there is just one row for the each code, and then in that row, display the value of the [cost] in the column number equal to the month. For example:
Column 1 2 3 4 5 6 7 8 9 10 11 12
Name 1 100
Name 2 120 180
Here's what I'm trying:
In order to find out how many rows should be printed, I fetch the unique code values:
$codes = array();
foreach( $data as $row ){
if ( in_array($row['code'], $codes) ) {
continue;
}
$codes[] = $row['code'];
}
Next, I use a loop to print the rows:
foreach( $codes as $code ){
//print 12 columns for each othe row
for ($i = 1; $<=12; $i++) {
//display column value if the code is same as the row
//and the month value is same as $i
//here's the problem
if (( $data['code'] == $code ) &&( $data['month'] == $i )) {
echo $data['cost'];
}
}
}
Problem/Question:
Do I need to put another loop inside the for loop to check if the $data['code'] == $code ? Or how can I do that?

Answer 1

I would use one loop to re-index the array:
$list = $codes = [];
for ($array as $item){
$list[$item['code']][$item['month']] = $item;
$codes[$item['code']] = $item['name'];
}
then use two loops to print:
for ($codes as $code => $codeName){
echo '<tr><th>', $codeName, '</th>';
for (range(1, 12) as $month){
echo '<td>', ($list[$code][$month]['cost'] ?? ''), '</td>;
}
echo '</tr>', "\n";
}
I really do not like the idea of if()s inside the loops.

Answer 2

I would suggest that you preprocess your data to a structured array first and then you print it, for example, indexed by code with a structure like:
[
['the code'] => [
'name' => '',
'months' => [
'6' => // cost
]
]
]
You can do it like this:
$items = [
[
'code' => 20,
'name' => 'Name 1',
'month' => 4,
'cost' => 100,
],
[
'code' => 30,
'name' => 'Name 2',
'month' => 3,
'cost' => 120,
],
[
'code' => 30,
'name' => 'Name 2',
'month' => 6,
'cost' => 180,
],
];
$sortedItems = [];
foreach ($items as $item) {
if (!isset($sortedItems[$item['code']])) {
$sortedItems[$item['code']] = [
'name' => $item['name'],
'months' => [],
];
}
$sortedItems[$item['code']]['months'][$item['month']] = $item['cost'];
}
You can the print it using a function similar to this:
function printItemsOf(array $list) {
echo '<table>';
// print header
echo '<tr>';
echo '<td>Column</td>';
for ($i = 1; $i <= 12; $i++) {
echo '<td>' . $i . '</td>';
}
echo '</tr>';
// print items
foreach ($list as $code => $item) {
echo '<tr>';
echo '<td>' . $item['name'] . '</td>';
for ($i = 1; $i <= 12; $i++) {
if (!isset($item['months'][$i])) {
echo '<td></td>';
} else {
echo '<td>' . $item['months'][$i] . '</td>';
}
}
echo '</tr>';
}
echo '</table>';
}
Which outputs:
<table border="1"><tr><td>Column</td><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td><td>8</td><td>9</td><td>10</td><td>11</td><td>12</td></tr><tr><td>Name 1</td><td></td><td></td><td></td><td>100</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Name 2</td><td></td><td></td><td>120</td><td></td><td></td><td>180</td><td></td><td></td><td></td><td></td><td></td><td></td></tr></table>