Template:Random number/doc

This is a documentation subpage for Template:Random number. It may contain usage information, categories and other content that is not part of the original template page.

This template is used on approximately 5,600 pages and changes may be widely noticed. Test changes in the template's /sandbox or /testcases subpages, or in your own user subpage. Consider discussing changes on the talk page before implementing them.

This template generates a pseudo-random integer between 0 and |count|-1.

Usage:

• {{Random number|count|seed|prime}}
• All parameters are optional and have default values. They must be integers.
• The calculation is (Prime(Unix + Seed) + (Articles mod Prime)) mod Count, where
  • the default count is 100 (so by default, this template generates values between 0 and 99) and must be less than -1 or greater than 1;
  • the default seed is {{#time:z}} (currently 235, i.e. the current day number in the year, at the time this page was last saved or purged from the cache) and can be set to any other integer value (used to generate distinct values on the same page);
  • the default prime is 67 and should be a prime number above 17 (used to generate distinct values on the same page);
  • Unix is the current Unix timestamp (1787579932); and
  • Articles is the raw number of articles on the English Wikipedia (7229834).
• This template may be substituted to persist the random number: {{subst:random number}}

Examples generating numbers between 0 and 999:

• {{Random number}} = 54 (default, gives values between 0 and 99)
• {{Random number|1000}} = 254 (second and third digit are the same as above)
• {{Random number|1000}} = 254 (same page load, same output)
• {{Random number|1000|235|67}} = 254 (same as above)
• {{Random number|1000|235|61}} = 240 (this and others should all be different)
• {{Random number|1000|6}} = 911
• {{Random number|1000|5}} = 844
• {{Random number|1000|4}} = 777
• {{Random number|1000|3}} = 710
• {{Random number|1000|2}} = 643
• {{Random number|1000|1}} = 576
• {{Random number|1000|0}} = 509
• {{Random number|1000|1|17}} = 850 (varying the prime number)
• {{Random number|1000|1|19}} = 719
• {{Random number|1000|1|23}} = 450
• {{Random number|1000|1|29}} = 46
• {{Random number|1000|1|31}} = 906
• {{Random number|1000|1|37}} = 518
• {{Random number|1000|1|41}} = 229
• {{Random number|1000|1|43}} = 105
• {{Random number|1000|1|47}} = 816
• {{Random number|1000|1|51}} = 555
• {{Random number|1000|1|53}} = 447
• {{Random number|1000|1|59}} = 21
• {{Random number|1000|1|61}} = 905
• {{Random number|1000|1|67}} = 509
• {{Random number|1000|1|71}} = 218
• {{Random number|1000|1|73}} = 96
• {{Random number|1000|1|79}} = 698

Note:

• Varying seed linearly generates numbers that generate a linear sequence on the same page, with equal cyclic steps;
• Varying prime (provided that they are odd prime numbers) generates pseudo-random that have independent random distribution.
• Note that when count is even (such as 100 by default, or 1000 in the examples above), the generated numbers (on the same page) are all odd or all even when you are varying the seed or prime, unless half of the calls use an even seed and the others used an odd seed. However, later invocations will still alternate odd and even numbers on output (this problem only occurs on the same page where multiple random numbers are invoked).
• On the same page, multiple invocations of this template with the same parameters will generate the same output value, so it is possible to create multiple links related to the same article.

• {{Random item}}
• {{Random country}}
• {{Random color}}
• {{Random Component}}
• {{Random motto}}
• {{Random page}}
• {{Random page in category}}
• {{Random portal component}}
• {{Random quotation}}
• {{Random slideshow}}
• {{Random subpage}}
• {{Random quote}}
• {{Random number subst}}, which is automatically substituted by AnomieBOT (talk · contribs). This can be handy to publicly and fairly choose a random number.