CODEWITHSUNDEEP
php
Kaka
Kaka

Reputation: 395

rand(000000, 999999) sometimes generate 4 digit numbers

I want to generate 6 digit numbers. Now this work great BUT occasionally it generates 4 digit numbers. Not often but some times it does. Why??

$num = rand(000000, 999999);

Upvotes: 1

Views: 6351

Answers (5)

Nicolas Henry
Nicolas Henry

Reputation: 22

http://php.net/manual/en/function.rand.php

Note :
Warning min max range must be within the range getrandmax(). i.e. (max - min) <= getrandmax() Otherwise, rand() may return poor-quality random numbers.

So, an other note :
Note: On some platforms (such as Windows), getrandmax() is only 32767. If you require a range larger than 32767, specifying min and max will allow you to create a range larger than this, or consider using mt_rand() instead.

Upvotes: 0

omar
omar

Reputation: 11

As everyone else said, you could change $num = rand(000000, 999999); to $num = rand(100000, 999999);, but there might be a case where you need a number that has 6 digits, but whose value is below 100000. Ex. 001103. You can still use $num = rand(000000, 999999); but you would use something like: 

$num = rand(000000, 999999);
$print_num = sprintf("%06d", $num);

This would not change the number, it will only give it a 6 digit format.

Upvotes: 0

kave
kave

Reputation: 471

rand(000000, 999999) is equal to rand(0, 999999)

It will return a number between 0 and 999999. In 90% of all cases the number is between 100000 and 999999 and you will have a 6 digit number. That is why it works for you most of the time

But in 10% of all cases, the number will be smaller than 100000 and only contain 1 to 5 digits (all numbers between 1 and 99999..not hard to figure out that 1 or 2 digits are still less propable then 4 or 5 digits)

To solve your problem you have to get a number from rand(100000, 999999), but this won't contain any numbers starting with 0! The first digit will always be from 1 and 9.

The other answers already show nice solutions for getting 6 digits from 0 to 9. Another easy one would just be:

for($i = 0; i < 6; i++)
    $rand_digit[$i] = rand(0,9);

Upvotes: 1

Guilherme Sehn
Guilherme Sehn

Reputation: 6787

If you want to generate numbers from 000000 to 999999 with 6-digit padding, you can use the str_pad function.

$rand = rand(0, 999999);
echo str_pad($rand, 6, '0', STR_PAD_LEFT);

Upvotes: 4

VladimirM
VladimirM

Reputation: 817

$num = rand(100000, 999999);

Maybe this do the job :)

Upvotes: 8

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