PHP Exercises: Reads a list of pairs of a word and a page number, and prints the word and a list of the corresponding page numbers

Last update on May 30 2022 11:43:35 (UTC/GMT +8 hours)

PHP: Exercise-77 with Solution

Write a PHP program which reads a list of pairs of a word and a page number, and prints the word and a list of the corresponding page numbers.
The number of pairs of a word and a page number is less than or equal to 1000. A word never appear in a page more than once. The words should be printed in alphabetical order and the page numbers should be printed in ascending order.

Sample Output:
The maximum value of the sum of integers passing according to the rule on one line.

Sample Solution: -

PHP Code:

<?php
$page = array();
while($line = fgets(STDIN)){
    list($a, $b) = explode(" ", trim($line));
    if(!isset($page[$a])){
        $page[$a] = array();
    }
    $page[$a][] = $b;
} 
ksort($page);
echo "The word and a list of the corresponding page numbers:\n";
foreach($page as $word => $arr){
    sort($arr, SORT_NUMERIC);
    echo $word."\n";
    echo implode($arr, " ")."\n";
}

?>

Sample Input:
apple 5
banana 6

Sample Output:

The word and a list of the corresponding page numbers:
apple
5
banana
6

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program which adds up columns and rows of given table as shown in the specified figure
Next: Write a PHP program to create a function that returns true for all elements of an array, false otherwise.

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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