Question 40446 in PHP Question posted in
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PHP Complex Number Selection

I have wrote the following code:

$row_array = range( 1 , $puzzle_size , 1 );
$yes_array = array_rand( $row_array , $total_numbers_to_display );

The values of $puzzle_size and $total_numbers_to_display depends on the difficulty level:

$puzzle_size will be 8, 20 and 40 for easy, medium and hard levels. $total_numbers_to_display = 3

The value of $yes_array is not giving me the output I need. What it gave me right now is:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
)

What I am requiring is for there to be at least 1 number gap between each result.

Example 1:

Array
(
    [0] => 1
    [1] => 3
    [2] => 5
)

Example 2:

Array
(
    [0] => 1
    [1] => 4
    [2] => 7
)

Example 3:

Array
(
    [0] => 2
    [1] => 4
    [2] => 7
)

I am unsure of how to do this.

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    The answer by @PracticalOpportunist got me on the right track. This is the function I wrote:

    function get_non_consequtive_numbers( $puzzle_size , $total_numbers_to_display ) {

    $non_consequtive_numbers = [ ];

    $eligible_numbers = range( 1 , $puzzle_size , 1 );

    while ( count( $non_consequtive_numbers ) < $total_numbers_to_display ) {

        # get a random number

            $candidate_number = rand( 1 , $puzzle_size );

        # check if number is in $eligible_numbers

            if ( in_array( $candidate_number , $eligible_numbers ) ) {

                # add to $non_consequtive_numvbers

                    $non_consequtive_numbers[ count( $non_consequtive_numbers ) + 1 ] = $candidate_number;

                # remove from $eligible_numbers

                    foreach ( range( ( $candidate_number - 1 ) , ( $candidate_number + 1 ) , 1 ) AS $ineligible_number ) {

                        if ( ( $key = array_search( $ineligible_number , $eligible_numbers ) ) !== false ) {

                            unset( $eligible_numbers[$key] );

                        }

                    }

            }

    }

    return $non_consequtive_numbers;

}

  2. 0

    Please edit your code as shown below :

    <?php 
// Total number of items required
$puzzle_size = 50;

// Total items to be displayed 
$total_numbers_to_display = 5;

// Seed the array items as per $puzzle_size value
$row_array = range( 1 , $puzzle_size , 1 );

// Function to get the random array items and pick only the number of items required. array_rand() will return only the keys of the array, not the values.
function randItems($sourceArray){
    
    // declare global variable
    global $total_numbers_to_display;

    // generate random array elements and return 
    return array_rand( $sourceArray , $total_numbers_to_display );
}

// Function to check whether any consequtive numbers are generated from randItems function above. If exists, then re-pick the random elements from $row_array 
function get_non_consequtive_numbers($outputArray)
{
    // declare global variable
    global $row_array;

   // iterate through the array provided as parameter
   foreach($outputArray as $num){

        // check if any previous or next number exists in the generated array. If exists, then re-pick the random elements from $row_array
        if( in_array(($num+1) , $outputArray ) or in_array(($num-1), $outputArray ) )
        {

            // calling randItems and recursive function to check.
            return get_non_consequtive_numbers(randItems($row_array));   
        }
    }
    
    // if no consequtive numbers found, then the array is valid and return.
    return $outputArray;      
}

// initiating the generation process
$yes_array = get_non_consequtive_numbers(randItems($row_array));

// printing the output obtained from above line
print_r($yes_array);

    Output is as expected in the question.

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