random subarray from an array

[Ante Perkovic]

Hi, everybody

First, the code:
---------------------
$maxNo = 500
$numbers = range (1,$maxNo);
srand ((double)microt ime()*1000000);
shuffle ($numbers);
$subarray = array_slice ($numbers, 0, 24);
ksort ($subarray); // this also don't work!!!
while (list (, $number) = each ($subarray)) {
echo "$number, ";
}
---------------------

I hoped this piece of code will generate random numbers from 1 to 500
but every time it generates the same sequence. Why?

Also, when I change $maxNo to some other number, it changes the
subarray, but then it stayes the same until I change the $maxNo again.
If I change it back to 500, it's the first sequence all over again.
This is the infamous sequence:
30, 3, 482, 286, 226, 414, 158, 258, 98, 478, 222, 354, 94, 386, 130,
350, 34, 481, 225, 290, 97, 418, 162, 353,

This is definitely not how I understand word "random"!

And one more thing: this example is how this thing works on my home
computer. I have the same application on web server, and it doesn't
work the same way! It changes subarray every time I refresh the page,
but the numbers are inclined to upper limit, so if I put $maxNo = 500,
10 out of 24 numbers will be between 480 and 500. Why they prefer
upper limit?

This is very confusing for me...

Please, help

Ante

[Pedro]

Ante Perkovic wrote:

Hi, everybody

First, the code:
---------------------
$maxNo = 500
$numbers = range (1,$maxNo);
srand ((double)microt ime()*1000000);
try
echo (double)microti me()*1000000;

I get different values every time ... but you might not :)

According to php.net, as of php 4.2.0 you needn't initialize the random
number generator ... try leaving the srand() call out

shuffle ($numbers);
$subarray = array_slice ($numbers, 0, 24);
ksort ($subarray); // this also don't work!!!
ksort() -- sort by key ... is this what you want?
or is it a simple sort() ?

while (list (, $number) = each ($subarray)) {
echo "$number, ";
}
maybe better:
echo implode(', ', $subarray);

---------------------

but the numbers are inclined to upper limit, so if I put $maxNo = 500,
10 out of 24 numbers will be between 480 and 500. Why they prefer
upper limit?

This is strange!
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