For function -> randomly select a certain amount of data

hatching

I'm using the "for" function to echo all the current names for a childs donation but how would I collect the names and randomly echo a certain limit in ascending order?

EXAMPLE:
for ( $counter = 10; $counter <= 100; $counter += 10) {
	echo "".$counter."<br>";
}
OUTPUT
10
20
30
40
...
80
90
100

Trying to randomly select 5 out of the 10 looped and have it in order:
10
40
50
60
90

for ( $j = 0; $j < count($names); $j++ ){

echo $names;

}

Any help for this slow learner?

halojoy

<?php
//another way to assign this array would be
//$first_arr = array( 10,20,30,40,50,60,70,80,90,100 );
//but lets use your automatic way
for( $counter = 10; $counter <= 100; $counter += 10 ) {

echo $counter.", ";
//will make $first_arr[0]=10, $first_arr[1]=20, etc etc
$first_arr[] = $counter;
} 

//show contents of this first array
echo '<pre>'. print_r( $first_arr, true ). '</pre>';
echo '<hr>';

$num = 5; // loop 5 times
for( $i=0; $i<5 ; $i++ ){

 // we use special function, array_rand(), to get one value of $first_arr
 // pick a random value of all in first_arr 
$rand_arr[] = $first_arr[ array_rand($first_arr) ];
//array_rand returns 0-9, which is one 'key' of $first_arr
//so we put that key, for example 1, to adress $first_arr[1], which actually is the value '20'
}

//show contents of this array
echo '<pre>'. print_r( $rand_arr, true ). '</pre>';
echo '<hr>';

// finish script with a link
exit(  '<a href="">Do it Again</a>' );

?>

for reading more, here is manual of [man]array_rand[/man]
Here is about arrays http://php.net/manual/en/language.types.array.php
Here are all array functions: [man]array[/man]

Regards 🙂

halojoy

this addition
if you want to sort $rand_arr, by the values

//show contents of this array
echo '<pre>'. print_r( $rand_arr, true ). '</pre>';
echo '<hr>';

sort($rand_arr);
echo '<pre>'. print_r( $rand_arr, true ). '</pre>';

// finish script with a link
exit(  '<a href="">Do it Again</a>' );

hatching

Thanks halojoy.

But how would I generate the same amount it without duplicates like the one below?

Array
(
[0] => 10
[1] => 10
[2] => 30
[3] => 90
[4] => 90
)

halojoy

yes, I thought about that ... already 😉

We need to delete a used value from $first_arr
When removing one element in an array (or any other variable),
we use the function [man]unset[/man]

unset( $first_arr[0] );
will remove: [0] => 10
which is the first pair
'key' =>value
in this array

like this, I use a variable $key to store each random result
this holds the 'key' number to an element in $first_array

<?php
//another way to assign this array would be
//$first_arr = array( 10,20,30,40,50,60,70,80,90,100 );
//but lets use your automatic way
for( $counter = 10; $counter <= 100; $counter += 10 ) {
    echo $counter.", ";
     //will make $first_arr[0]=10, $first_arr[1]=20, etc etc
    $first_arr[] = $counter;
} 
//show contents of this first array
//echo '<pre>'. print_r( $first_arr, true ). '</pre>';

$num = 5; // loop 5 times
for( $i=0; $i<5 ; $i++ ){
     // we use special function, array_rand(), to get one value of $first_arr
     // pick a random value of all in first_arr 
    $key = array_rand($first_arr);
    $rand_arr[] = $first_arr[$key];
    unset( $first_arr[$key] ); 
    //array_rand returns 0-9, which is one 'key' of $first_arr
    //we put that key, e.g. 1, to adress $first_arr[1], which is the value '20'
}
// we can see how much is left of $first_arr, not used values
echo '<pre>'. print_r( $first_arr, true ). '</pre>';
echo '<hr>'; ///////////

// show contents of this new array
echo 'new array:';
echo '<pre>'. print_r( $rand_arr, true ). '</pre>';
sort($rand_arr);
echo 'sorted:';
echo '<pre>'. print_r( $rand_arr, true ). '</pre>';

exit(  '<a href="">Do it Again</a>' );
?>