PHP Shouldnot Repeat and should be from an array - php

Question

I'm trying to build a script that does two thing.
1) The Numbers should not repeat.
2) The numbers should be from an array called $id.
<?php
$a = array(); // final array which will have our id's to display
$id = array(1, 3, 5, 7, 9); //final array should contain a number only from this list
$itemstoshow = 3; // how many items to display
for($i = 0; $i < $itemstoshow; $i++) {
do {
$a[$i] = assignid(9);
$chkid = checkeer($a[$i], $i);
$chkdata = chkdata($a[$i], $i);
} while($chkdata == "nonexist" or $chkid == "repeatedid");
}
// display numbers in the array
for($i = 0; $i < $itemstoshow; $i++) {
echo "Item " . $a[$i] . "--------";
}
// check for redundancy function
function checkeer($x, $y)
{ //first parameter is query aray second is counter
global $a;
$err = 0;
// check if repeating number
for($i = 0; $i <= $y - 1; $i++) {
if($x == $a[$i]) {
$err = 1;
}
}
if($err == 1) {
return "repeatedid";
}
}
//check if array $a holds value from $id or not
function chkdata($x, $y)
{
global $a;
global $id;
for($i = 0; $i <= $y - 1; $i++) {
if($x !== $id[$i]) {
return "nonexist";
}
}
}
//assign id function
function assignid($x)
{
return rand(1, $x);
}
problem number 1 solved problem number 2 still not solved please help me.
the code should show 3 numbers from 1 to 9 which donot repeat and are in the array $id

Answer 1

You could use a combination of array_rand and array_map to get random values from the array that has the values your basing the randomization. Take a look:
$id = array(1,3,5,7,9); //final array should contain a number only from this list
$itemstoshow = 3;
$values = array_map(function($item) use($id){
return $id[$item];
}, array_rand($id, $itemstoshow));
print_r($values);
Output:
Array
(
[0] => 1
[1] => 3
[2] => 9
)
Running again:
Array
(
[0] => 3
[1] => 7
[2] => 9
)

Answer 2

You can use array_rand that selects random keys:
$id = array(1,3,5,7,9);
$result = array_intersect_key($id, array_flip(array_rand($id, 3)));
Or you can shuffle the array and take for example the 3 first items:
$id = array(1,3,5,7,9);
$temp = $id;
shuffle($temp);
for ($i = 0; $i < 3; $i++) {
$result[] = $temp[$i];
}