uasort() ? - sorting posts from a bank account - php

Question

How can I sort an array with some posts from a bank account?
I need to sort by three fields: date, amount, accumulated amount
ie.
date | amount | accum_amount
01-01-11 500 500 ('amount' + previous 'accum_amount' = 'accum_amount' => 500 + 0 = 500)
01-01-11 100 600 ('amount' + previous 'accum_amount' = 'accum_amount' => 100 + 500 = 600)
01-02-11 -25 575 ('amount' + previous 'accum_amount' = 'accum_amount' => -25 + 600 = 575)
01-02-11 150 725 ('amount' + previous 'accum_amount' = 'accum_amount' => 150 + 575 = 725)
01-03-11 200 925 ('amount' + previous 'accum_amount' = 'accum_amount' => 200 + 725 = 925)
01-04-11 -25 900 ('amount' + previous 'accum_amount' = 'accum_amount' => -25 + 925 = 900)
btw. the date field is an UNIX timestamp
array(
array(
'time' => 1200000000,
'amount' => 500,
'accum_amount' => 500
),
array(
'time' => 1200000000,
'amount' => 150,
'accum_amount' => 725
),
array(
'time' => 1200000000,
'amount' => 100,
'accum_amount' => 600
),
array(
'time' => 1300000000,
'amount' => 200,
'accum_amount' => 925
),
array(
'time' => 1300000000,
'amount' => -25,
'accum_amount' => 900
),
array(
'time' => 1200000000,
'amount' => -25,
'accum_amount' => 575
)
)

Answer 1

Change your array structure to something like:
$tmp = array(
time => array(1200000000, 1200000000, 1200000000, ...),
amount => array(500, 150, 100, ...),
accum_amount => array(500, 725, 600, ...),
)
and then use array_multisort for sorting (http://php.net/manual/en/function.array-multisort.php) like:
array_multisort($tmp['time'], SORT_ASC, $tmp['amount'], SORT_DESC, $tmp['accum_amount'], SORT_ASC);
It's not very intuitive, but it should work.
Of course you can write a helper function to map the new sorting order on other array structure.
Example:
function mySort($array, $sort) {
$tmp = array();
foreach ($array as $row) {
foreach ($row as $field => $value) {
if (!isset($tmp[$field])) {
$tmp[$field] = array();
}
$tmp[$field][] = $value;
}
}
$params = array();
foreach ($sort as $field => $direction) {
$params[] = $tmp[$field];
$params[] = $direction;
}
$keys = array_keys($array);
$params[] =& $keys;
call_user_func_array('array_multisort', $params);
$result = array();
foreach ($keys as $key) {
$result[$key] = $array[$key];
}
return $result;
}
Call:
$data = mySort($data, array(
'time' => SORT_ASC,
'amount' => SORT_ASC,
'accum_amount' => SORT_ASC
));

Answer 2

function usort() is made for this purpose:
usort($data, "my_sort");
function my_sort($row1, $row2) {
if ($row1['time']<$row2['time']) return -1;
if ($row1['time']>$row2['time']) return 1;
if ($row1['amount']<$row2['amount']) return -1;
if ($row1['amount']>$row2['amount']) return 1;
if ($row1['accum_amount']<$row2['accum_amount']) return -1;
if ($row1['accum_amount']>$row2['accum_amount']) return 1;
return 0;
}

Answer 3

Your example isnt really clear what you want. You don't describe it this way, but from example it appears you want to sort by date increasing, then accum_amount increasing, then amount (increasing?)
You just have to write a comparison function and pass it to uasort along with your array
$comp = function($a,$b)
{
if ($a['date'] != $b['date'])
return $a['date'] - $b['date'];
else if ($a['accum_amount'] != $b['accum_amount'])
return $a['accum_amount'] - $b['accum_amount'];
return $a['amount'] - $b['amount'];
}
uasort($arr, $comp);
You might find a function like this helpful. It will create the comparison function when given an array, in order of importance, of the keys to compare by. (All ascending, support for descending would necessarily complicate it a good deal)
$compMakerAsc = function($l)
{
return function($a, $b) use ($l)
{
foreach($l as $k)
{
if ($a[$k] != $b[$k])
return $a[$k] - $b[$k];
//OR return ($a[$k] > $b[$k]) ? 1 : -1;
}
return 0;
}
$myComp = $compMakerAsc('date', 'accum_amount', 'amount');
$uasort($arr, $myComp);

Answer 4

$key = 'accum_amount';
function sortme($a, $b)
{
global $key;
if ($a[$key] == $b[$key]) {
return 0;
}
return ($a[$key] < $b[$key]) ? -1 : 1;
}
usort($array, "sortme");
perhaps this should help. Bad thing, have to define global variable. Complete code!!!
$array = array(
array(
'time' => 1200000000,
'amount' => 500,
'accum_amount' => 500
),
array(
'time' => 1200000000,
'amount' => 150,
'accum_amount' => 725
),
array(
'time' => 1200000000,
'amount' => 100,
'accum_amount' => 600
),
array(
'time' => 1300000000,
'amount' => 200,
'accum_amount' => 925
),
array(
'time' => 1300000000,
'amount' => -25,
'accum_amount' => 900
),
array(
'time' => 1200000000,
'amount' => -25,
'accum_amount' => 575
)
);
$key = 'accum_amount';
function sortme($a, $b)
{
global $key;
if ($a[$key] == $b[$key]) {
return 0;
}
return ($a[$key] < $b[$key]) ? -1 : 1;
}
usort($array, "sortme");
echo "<pre>";
print_r($array);
echo "</pre>";

Answer 5

Let's combine this from the comments
the query is just as simple as SELECT time, amount, accum_amount FROM table
with this requirement from the original question:
I need to sort by three fields: date, amount, accumulated amount
Now, there were no requirements stated as to whether the sort is ascending or not. Let's assume ascending.
SELECT time, amount, accum_amount
FROM table
ORDER BY time ASC, amount ASC, accum_amount ASC
This will give us all of the data first sorted by time. When the time is identical, it will sort second by amount, lowest first and highest last. When the time and amount are identical, it will sort third by the accumulated amount, again sorted lowest first, highest last.
Changing the order of operations with the sort is as simple as swapping around the list in the ORDER BY clause. Going from largest to smallest is as easy as switching from ASC to DESC.
Note how relatively easy this method is in comparison to sorting in PHP. Whenever you can, let your database give you pre-sorted results.
Because I need to leave the site for a few hours, I'm just going to type this up real quick. I'm operating right now under the assumption that you want to recalculate the accumulated value.
Our query is now:
SELECT time, amount
FROM table
ORDER BY time ASC, amount DESC
We'll be a friendly bank and perform all deposits (increases in amount) first, then all debits (decreases in amount) last, processing the largest debits later than the smaller debits.
Given $data is our array:
$running_total = 0;
foreach($data as $index => $row) {
$data[$index]['accum_amount'] = $running_total + $row['amount'];
$running_total = $data[$index]['accum_amount'];
}
This should successfully rebuild the accum_amount list, given the business rules I have outlined above.

Answer 6

I have found another way to do it before the data is put into the db