How to generate a random pattern of *&# in PHP - php

Question

Hello there i am making a program which will let me help generate a random string with a specified limit and random strings of *&# but then the combination of *&# should not repeat.
Ex: if I input 3 then the O/P should be
#**
**#
**#
It should generate a random string of length 3 up to 3 rows with different patterns also the pattern should not repeat. I am using the below code but not able to attain it.
$n = 3;
for($i = 0; $i < n; $i++)
{
for($j=0;$j<=$n;j++)
{
echo "*#";
}
echo "<br />";
}
But I am not able to generate the output, where is my logic failing?

Answer 1

If you want to make sure the same pattern doesn't show up more than once you'll have to keep a record of the generated strings. In the most basic form it could look like this:
public function generate() {
$amount = 3; // The amount of strings you want.
$generated_strings = []; // Keep a record of the generated strings.
do {
$random = $this->generateRandomString(); // Generate a random string
if(!in_array($random, $generated_strings)) { // Keep the record if its not already present.
$generated_strings[] = $random;
}
} while(sizeof($generated_strings) !== $amount); // Repeat this process until you have three strings.
print_r($generated_strings);
}
public function generateRandomString($length = 3) {
$characters = '*&#';
$charactersLength = strlen($characters);
$randomString = '';
for ($i = 0; $i < $length; $i++) {
$randomString .= $characters[rand(0, $charactersLength - 1)];
}
return $randomString;
}

Answer 2

Not necessarily the most optimized algorithm but it should work.
I am using a string generator, somewhat random, combining the chars you have provided. The second part is filling the output array with generated strings that are not already present.
<?php
function randomize($n) {
$s = '';
for ($i = 0; $i < $n; $i++) {
$s. = (rand(0, 10) < 5 ? '*' : '#');
}
return $s;
}
$n = 3;
$output = array();
for ($i = 0; $i < $n; $i++) {
$tmp = randomize($n);
while (in_array($tmp, $output)) {
$tmp = randomize($n);
}
$output[] = $tmp;
}
print_r($output);
Visible here

Answer 3

You can use a while loop and array unique to do this.
I first have an array with possible chars.
Then I loop until result array is desired lenght.
I use array unique to remove any duplicates inside the loop.
I use rand(0,2) to "select" a random character from possible characters array.
$arr = ["*", "&", "#"];
$res = array();
$n =7;
While(count($res) != $n){
$temp="";
For($i=0;$i<$n;$i++){
$temp .= $arr[Rand(0,count($arr)-1)];
}
$res[] = $temp;
$res = array_unique($res);
}
Var_dump($res);
https://3v4l.org/Ko4Wd
Updated with out of scope details not clearly specified by OP.