Stop the MSR by an external switch on Hubitat.

[LibraSun]

@toggledbits , how does MSR "know" that an expression like:

each dev in devs: getEntity(dev).attributes.power_switch.state ? dev : null

contains dependencies on the status of (potentially) many devices?

It's neat that MSR almost immediately detects when a light gets turned on, for instance, and the resulting array grows by one within less than a second. But what is cuing MSR to re-evaluate the above expression so quickly behind the scenes?

[toggledbits]

If devs is a constant list, the iteration visits each dev through getEntity(), and that function subscribes to any device it is asked to resolve. So the first time the expression is evaluated, it has subscribed to every device in devs.

[LibraSun]

@toggledbits meanwhile, as I watch the steady stream of "changed entities" (involving devices that are otherwise just minding their own business, doing nothing) going by on Status, such as:

Sound Bar Beam
vera>device_322
Playing
17:39:11
Sofa Lamp
vera>device_138
false
17:39:00

do you recommend any changes to Vera in order to throttle that traffic, or is it just customary Z-Wave polling in action?

[toggledbits]

The rule or expression isn't reacting to every device, only those devices that end up being a target of getEntity(). The polling activity will cause additional evaluations, but it causes little actual additional load on the (MSR) system, certainly not enough to make it worth your time to try to put a dent in it. Party on!

[LibraSun]

SORTING AN ARRAY IN MSR EXPRESSIONS

I somehow doubt this will find much utility among most users' workflows, but here goes...
If you want to sort a particular 1-dimensional numerical array:

a=[8,3,11,0,5], #unsorted array
L=len(a)-1, 
each i in 0..L: #repeat for each value in a
do
b=a[0], #beginning with first value in array
each j in 0..(L-i): #compare remaining values
if min(b,num=a[j])<b then b=num else b endif,
remove(a,indexOf(a,b)), #remove b from array
b #was lowest number found in original array
done

// result (array) [ 0 , 3 , 5 , 8 , 11 ]

PRO TIP: To sort an array from another expression, simply edit the first line to something like this:

a = clone(otherExp),

UPDATE: As of release 21153, in which min() may take an array as its argument, the following expression works more cleanly:

a=[8,3,11,0,5],
each n in a: do b=min(a), remove(a,indexOf(a,b)), b done

[LibraSun]

CREATING AN ARRAY OF STEPPED VALUES

In case you're looking for a numerical array containing evenly-spaced (linear) DIM values in the range 0 to 1 and back to 0, this expression should fill the bill:

each s in split(join(0..10)+","+join(9..0),","): int(s)/10

// result (array) [0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1,0.9,0.8,0.7,0.6,0.5,0.4,0.3,0.2,0.1,0]

[toggledbits]

Also works: each n in -10..10: (10-abs(n))/10.

[LibraSun]

ARRAY OF RAMPED DIM VALUES USING SINE WAVE PATTERN

pi=3.1415, steps=10; each step in 0..steps:
round(sin(step*(pi/(2*steps))),2)

// result (array) [0,0.16,0.31,0.45,0.59,0.71,0.81,0.89,0.95,0.99,1]

NOTE: You can change the number of steps to any integer value.

[LibraSun]

ROTATE SET OF LIGHTS

Sometimes you might want a set of lights to swap "On"/"Off" states -- not "toggle" per se, just follow each other based on their starting status, which I'm calling "rotation." (I believe the technical term is "chasing.")

lites=["vera>device_8","vera>device_9","vera>device_110"], patt=each L in lites: getEntity(L).attributes.power_switch.state, 
new=slice(push(patt,patt[0]),1), each v,k in new: performAction(lites[k],"power_switch."+(v?"on":"off"),{})

USAGE
Edit the list in lites based on which devices you want to participate in the rotation. Every time this expression evaluates, the on/off states will rotate by one: i.e. 010 ► 100 ► 001, etc.

[tunnus]

@toggledbits any chance we'll see strftime function coming up "soon"? Or advice how to implement the same with lexpjs (when you have unix timestamp, RfV example below)?

strftime("%H:%M %d/%m/%y", <timestamp> )