Populating an array with a predefined set of numbers in PHP - php

Question

I need to create two arrays, for simulating a draw from a Lotto ticket.
The first array will consist of 6 unique numbers between 1 and 49.
The second array will consist of 7 unique numbers between 1 and 49.
I'm fairly new to PHP and I can't figure out how to populate an array, give it a predefined size, randomly put six numbers between 1 through 49 into the array, and then finally sort the array's in ascending order.
This is my quick rough draft of what I think is somewhat heading in the right direction?
$tmp;
$lotto = array(rand(1,49)); //Creating the random number for $lotto
$lottoMax = array(rand(1,49)); //Creating the random number for $lottoMax
for($tmp=0; $lotto <= 6; $tmp++){
//creating the size of the array?
}
Any advice/tips/help would be greatly appreciated!
Thank you.

Answer 1

There are several ways to approach something like this. The first that comes to mind is to first just create an array of the numbers 1-49 using range(1, 49). Then shuffle the array with shuffle() so its order is randomized. Finally, since it is already randomized, you can just chop off the first 6 or 7 numbers to fill your two arrays (which I'll do with array_slice()). The contents are guaranteed not to have any repeats and it only takes a couple of operations.
// The bag of numbers is a range
$bag = range(1, 49);
// Shuffle it
shuffle($bag);
// Get the first array
$first_group = array_slice($bag, 0, 6);
// Shuffle it again and get the second array
shuffle($bag);
$second_group = array_slice($bag, 0, 7);
print_r($first_group);
Array
(
[0] => 36
[1] => 22
[2] => 34
[3] => 17
[4] => 23
[5] => 25
)
print_r($second_group);
Array
(
[0] => 40
[1] => 32
[2] => 33
[3] => 36
[4] => 29
[5] => 7
[6] => 3
)

Answer 2

You could just generate the initial numbers by range() function from 1 to 49, then shuffle, then slice it:
$first = range(1, 49); shuffle($first);
$second = range(1, 49); shuffle($second);
$lotto = array_slice($first, 0, 6);
$lottoMax = array_slice($second, 0, 7);

Answer 3

The array_rand() function returns a random selection from an array.
$all_numbers = range(1, 49); // Create an array of 1 .. 49
$pick6 = array_rand($all_numbers, 6);
sort($pick6);
$pick7 = array_rand($all_numbers, 7);
sort($pick7);

Answer 4

You seem to have a decent development background, which can make PHP arrays a little confusing at first. It helps me to think of them as hashes.
You can create an array in a few ways, I usually like to declare it:
$new_array = array();
or, to populate and initialize:
$new_array = array(1,2,3,"String")
PHP arrays are usually (always?) dynamically sized and typed...you can mix them up as much as you want.
You can also quickly add an item to an array by assignment:
$new_array[] = "whatever"; //will add it to the end of the array
$new_array['index'] = "more whatever"; // will insert it with the index 'index'
$new_array[11] = "last whatever"; // will put it in at numeric index 11
The latter two will overwrite any value in that index, which is probably obvious.
Anyway - hope that helps, and wasn't too obvious from the other answers already.
Here was what I had planned to suggest, but everyone beat me to it:
$possible_values = range(1,49);
$array_of_six = array_rand($possible_values,6);
$array_of_seven = array_rand($possible_values,7);
it comes back sorted by default.