random

random Function

Syntax:

random limit &optional random-state → random-number

Arguments and Values:

limit—a positive integer , or a positive float.

random-state—a random state. The default is the current random state.

random-number—a non-negative number less than limit and of the same type as limit.

Description:

Returns a pseudo-random number that is a non-negative number less than limit and of the same type as limit.

The random-state, which is modified by this function, encodes the internal state maintained by the random number generator.

An approximately uniform choice distribution is used. If limit is an integer , each of the possible results occurs with (approximate) probability 1/limit.

Examples:

(<= 0 (random 1000) 1000) → true 
(let ((state1 (make-random-state)) 
      (state2 (make-random-state))) 
  (= (random 1000 state1) (random 1000 state2))) → true 

Side Effects:

The random-state is modified.

Exceptional Situations:

Should signal an error of type type-error if limit is not a positive integer or a positive real.

See Also:

make-random-state, *random-state*

Notes:

See Common Lisp: The Language for information about generating random numbers.

Expanded Reference: random

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(random )