php how to cut array and add other charactor to it - php

Question

I have an array like :
Array
(
[0] => a
[1] => b
[2] => c
[3] => d
[4] => e
[5] => f
[6] => g
[7] => h
)
And I want add semicolon(;) every 3 index value and it's read from end of array that result is string like "ab;cde;fgh";

Answer 1

Here's a fun, and kind of obnoxious, one-liner:
$str = ltrim(strrev(chunk_split(implode(array_reverse($arr)), 3, ';')), ';');
Example:
$arr = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h');
$str = ltrim(strrev(chunk_split(implode(array_reverse($arr)), 3, ';')), ';');
echo $str; //ab;cde;fgh
// More sample output based on different input arrays:
$arr = array('a', 'b', 'c', 'd', 'e'); //ab;cde
$arr = array('a', 'b', 'c', 'd', 'e', 'f'); //abc;def
$arr = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k'); //ab;cde;fgh;ijk
See demo

Answer 2

Its an odd way, but since you want it reversed you may need to use some function here:
$array = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h');
$array = array_reverse($array); // reverse it
$array = array_chunk($array, 3); // cut by threes
$string = '';
foreach ($array as $value) {
$string .= implode($value); // glue them
if(count($value) == 3) { // if still three, add a semi
$string .= ';';
}
}
$string = strrev($string); // then reverse them again
echo $string; // ab;cde;fgh

Answer 3

This works... there's a couple different ways to do this. This was the quickest way off the top of my head without using a second array.
$vars = array("a","b","c","d","e","f","g","h");
print_r(insert_char($vars));
function insert_char($Array, $Delimeter=";", $Count=3) {
for ($i = sizeOf($Array) - $Count; $i > 0; $i -= $Count)
array_splice($Array, $i, 0, $Delimeter);
return implode($Array);
}
Result
ab;cde;fgh

Answer 4

Here's my solution, although it feels inefficient it is pretty clear:
<?php
$myarr=Array('a','b','c','d','e','f','g','h');
$newarr=Array();
$arrsize = sizeof($myarr);
for ($x = 0, $i = 0; $x < $arrsize; $x++, $i++) {
$newarr[$i] = $myarr[$arrsize - $x - 1];
if (($arrsize - $x) % 3 == 0) {
$i++;
$newarr[$i] = ";";
}
}
$newarr = array_reverse($newarr);
print_r($newarr);
?>

Answer 5

Just traversing it from backward and joining the string in reverse too gives that result.
$vars = array("a","b","c","d","e","f","g");
$c = 0; $s = "";
for ($i = sizeof($vars)-1; $i >= 0; $i--)
{
$c++;
$s = $vars[$i].$s;
if ($c == 3) { $c = 0; $s = ";".$s; }
}
echo $s;