PHP create combinations in array

Question

Let's say I have an array containing: apples, watermelons, grapes. What I'm trying to do is create another array with

apples, apples;watermelons, apples;watermelons;grapes

I tried using implode, but it's not exactly what I wanted. Is there a built in function for this task? Thanks!

EDIT: For clarification, the created string is basically a combination of these three elements. So the created array could also look like:

apples, apples-watermelons, apples-watermelons-grapes

Answer 1

An elegant way to do it is with array_reduce

<?php
$my_array = array('apples','watermelons','grapes');

function collapse($result, $item) {
    $result[] = end($result) !== FALSE ? end($result) . ';' . $item : $item;
    return $result;
}

$collapsed = array_reduce($my_array, "collapse", array());
var_dump($collapsed);
?>

Testing:

matt@wraith:~/Dropbox/Public/StackOverflow$ php 11876147.php 
array(3) {
  [0]=>
  string(6) "apples"
  [1]=>
  string(18) "apples;watermelons"
  [2]=>
  string(25) "apples;watermelons;grapes"
}

Answer 2

<?php
$my_array = array('apples','watermelons','grapes');
$string = '';
$result = array();
for ($i=0; $i<count($my_array); $i++) {
   $string .= $my_array[$i];
   $result[] = $string;
   $string .= '-';
}
print_r($result);

There may be a way to do it with array_walk() or array_map() or one of the other array_*() functions as well.

Answer 3

<?php

$array = array("apples", "watermelons", "grapes");
$newarray = $array;
for ($i = 1; $i < count($array); $i++)
{
   $newarray[$i] = $newarray[$i - 1] . ";" . $newarray[$i] ;
}

print_r($newarray);
?>

Output:

Array
(
    [0] => apples
    [1] => apples;watermelons
    [2] => apples;watermelons;grapes
)