PHP Exercises: Find the customer number that has traded for the second consecutive for the second consecutive month from last month and the number of transactions

Last update on May 30 2022 11:45:04 (UTC/GMT +8 hours)

PHP: Exercise-70 with Solution

Record section of ABC company records the customer number and the trading date for each month. Write a PHP program to find the customer number that has traded for the second consecutive for the second consecutive month from last month and the number of transactions.
The data of this month and the data of last month are separated by a blank line of one line and given.
Transaction format:
c1 , d1
c2 , d2
...
...
ci (1 ≤ ci ≤ 1,000) is an integer represents the customer number, di (1 ≤ di ≤ 31) is an integer represents the trading date.

Sample Solution: -

PHP Code:

<?php
$x = array();
while (true) {
    $a = rtrim(fgets(STDIN));
    if ($a === '') {
        break;
    }
    list($n, $d) = explode(',', $a);
    if (!isset($x[$n])) {
        $x[$n] = 0;
    }
    $x[$n]++;
}
 
$y = array();
while (true) {
    $a = rtrim(fgets(STDIN));
    if ($a === '') {
        break;
    }
    list($n, $d) = explode(',', $a);
    if (!isset($x[$n])) {
        continue;
    }
    if (!isset($y[$n])) {
        $y[$n] = $x[$n];
    }
    $y[$n]++;
}
echo "Customer number and the number of transactions:\n";
ksort($y);
foreach ($y as $k => $v) {
    echo sprintf('%d %d', $k, $v) . PHP_EOL;
}

?>

Sample Input:
125,10
55,12
34,14

125,3
55,4
125,5

Sample Output:

Customer number and the number of transactions:
55 2
125 3

Flowchart:

PHP Code Editor:

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC