counting row values with different ids in multidimensional array - php

Question

I know there are a lot of topics about this, but just couldn't find any that would actually help me solve the problem.
Ok so i am having a problem with counting rows and values in multidimensional array (imported via .csv)
I am trying to achieve something like...
Array ( [0] => Array ( [0] => 1 [1] => 6278,31 [2] => 4)
[1] => Array ( [0] => 2 [1] => 2,0 [2] => 2)
[2] => Array ( [0] => 3 [1] => 3,01 [2] => 3)
)
where [0] would be buyer id, 1 is total number of buys and [2] total cost.
My current code:
if(($s_open = fopen("sales.csv", "r")) !== FALSE)
{
$s_count = count(file("sales.csv"));
while(($sales = fgetcsv($s_open, 100, ";")) !== FALSE)
{
...
}
fclose($s_open);
}
Thanks in advance.

Answer 1

You could group your data by creating an array with the buyer_id as index.
Each time you find a new buyer, you could create a small array ('id','count','amount').
Then, sum the values of the current row into that array.
const KEY_ID = 0; // shortcut for array indexes
const KEY_AMOUNT = 1;
const KEY_COUNT = 2;
$buyers = []; // final array
if (($s_open = fopen("sales.csv", "r")) !== FALSE)
{
$s_count = count(file("sales.csv"));
while(($sales = fgetcsv($s_open, 100, ";")) !== FALSE)
{
// Extract data from row:
[$id, $buyer_id, , $amount] = $sales;
// If the buyer doesn't exists in the array,
// create a new array with required format:
if (!isset($buyers[$buyer_id])) {
$buyers[$buyer_id] = [
KEY_ID => $buyer_id,
KEY_COUNT => 0,
KEY_AMOUNT => 0,
];
}
// Update values:
$buyers[$buyer_id][KEY_COUNT]++;
$buyers[$buyer_id][KEY_AMOUNT] += $amount;
}
fclose($s_open);
}
// Re-index values:
$buyers = array_values($buyers);

Answer 2

Using this mock data in.csv:
id, buyer_id, amount
1, 1, 100.55
2, 1, 500.1
3, 2, 50.55
4, 3, 1.0
I wrote the following PHP to parse it into a nicely formatted array (if you don't want to have named keys, you can just remove the header logic):
<?php
// Each line into an array
$csv = file(__DIR__ . DIRECTORY_SEPARATOR . 'in.csv');
// First line is the header
$header = str_getcsv(array_shift($csv));
// When the CSV header is `id, buyer_id, amount`, remove the whitespace
$header = array_map(function ($item) {
return trim($item);
}, $header);
// Get the CSV data as an array of arrays
$out = array_map(function ($line) use ($header) {
$data = str_getcsv($line);
return array_combine($header, $data);
}, $csv);
print_r($out);
Which prints the following to your screen:
Array
(
[0] => Array
(
[id] => 1
[buyer_id] => 1
[amount] => 100.55
)
[1] => Array
(
[id] => 2
[buyer_id] => 1
[amount] => 500.1
)
[2] => Array
(
[id] => 3
[buyer_id] => 2
[amount] => 50.55
)
[3] => Array
(
[id] => 4
[buyer_id] => 3
[amount] => 1.0
)
)

Answer 3

Try this
$data = [];
if(($s_open = fopen("sales.csv", "r")) !== FALSE) {
$s_count = count(file("sales.csv"));
while( ([$id, $buyer_id, $amount] = fgetcsv($s_open, 100, ";")) !== FALSE ){
if( $id !== 'id' ){
$data[$buyer_id] = [
$buyer_id,
($data[$buyer_id][1] ?? 0) + 1,
($data[$buyer_id][2] ?? 0) + $amount
];
}
}
fclose($s_open);
$data = array_values($data);
}
// print_r($data);