RANDOM

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>>-RANDOM--(--+----------------------------------+--)----------><
              +-max------------------------------+      
              '-+-min--,-+--+-----+--+---------+-'      
                '-,------'  '-max-'  '-,--seed-'        

returns a quasi-random nonnegative whole number in the range min to max inclusive. If you specify max or min or both, max minus min cannot exceed 100000. The min and max default to 0 and 999, respectively. To start a repeatable sequence of results, use a specific seed as the third argument, as described in Note 1. This seed must be a positive whole number ranging from 0 to 999999999.

Here are some examples:
RANDOM()          ->    305
RANDOM(5,8)       ->      7
RANDOM(2)         ->      0  /*  0  to  2    */
RANDOM(,,1983)    ->    123  /* reproducible */
Note:
  1. To obtain a predictable sequence of quasi-random numbers, use RANDOM a number of times, but specify a seed only the first time. For example, to simulate 40 throws of a 6-sided, unbiased die:
    sequence = RANDOM(1,6,12345)  /* any number would */
                                  /* do for a seed    */
    do 39
       sequence = sequence RANDOM(1,6)
       end
    say sequence
    The numbers are generated mathematically, using the initial seed, so that as far as possible they appear to be random. Running the program again produces the same sequence; using a different initial seed almost certainly produces a different sequence. If you do not supply a seed, the first time RANDOM is called, the microsecond field of the time-of-day clock is used as the seed; and hence your program almost always gives different results each time it is run.
  2. The random number generator is global for an entire program; the current seed is not saved across internal routine calls.

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Timestamp icon Last updated: Tuesday, 7 January 2014


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