/**
* Groups words by their first letter.
*
* @param array $words List of words to group
* @return array Associative array: letter => list of words
*/
function groupByFirstLetter(array $words): array
{
$groups = []; // associative array for grouping
foreach ($words as $word) {
// Extract the first character
$first = strtoupper($word[0]);
// If the key doesn't exist, create an empty array
if (!isset($groups[$first])) {
$groups[$first] = [];
}
// Add the word to its group
$groups[$first][] = $word;
}
return $groups;
}
// List of words to group
$words = [
"Python", "JavaScript", "C", "Java", "C#", "PHP",
"C++", "Pascal", "SQL", "Rust"
];
$grouped = groupByFirstLetter($words);
// Print each group
foreach ($grouped as $letter => $group) {
echo $letter . ": [" . implode(", ", $group) . "]\n";
}
// Print the entire array
print_r($grouped);
/*
run:
P: [Python, PHP, Pascal]
J: [JavaScript, Java]
C: [C, C#, C++]
S: [SQL]
R: [Rust]
Array
(
[P] => Array
(
[0] => Python
[1] => PHP
[2] => Pascal
)
[J] => Array
(
[0] => JavaScript
[1] => Java
)
[C] => Array
(
[0] => C
[1] => C#
[2] => C++
)
[S] => Array
(
[0] => SQL
)
[R] => Array
(
[0] => Rust
)
)
*/
