Operator Type:
Operator Scope of Action:
Operator Purpose:
Operator First Added:
Operator Altered:
Function [other Function type actions]
Item [operators of similar scope]
Mathematical [other Mathematical operators]
Baseline
rand()
rand() returns a pseudo-random number between 0 and 1. No argument is required.
Getting 1-based ranges vs. zero-based ranges of values
Consider:
$MyNum=round(rand()*10)
$MyNum will now be one of eleven integers in the range 0 through to 10.
But, what if the '10' argument about is actually a child count:
$MyNum=round(rand()*$ChildCount)
If the $ChildCount was 10 and $MyNum were used to fetch a random child using $SiblingOrder($MyNum) the process would fail if $MyNum were zero. $SiblingOrder numbers from 1. Indeed, in this case the need is for ten integers, one through to ten.
A 1-based range can be achieved:
$MyNum=round(rand()*(10-1))+1
$MyNum=round(rand()*($ChildCount-1))+1
If the main input is 10, by subtracting 1 the process returns a randomised integer in in the range 0-9 (ten numbers) and then adding back 1 shifts the value range to 1-10.