round off number to use as variable

Can you tell me why when this script writes the rounded off number to variable test123_, it is not rounded off?

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writeVar("test123_", 98.897896875578)

on writeVar(indigoSensor, val)
   tell application "IndigoServer"
      set val to my (roundThis(val, 2))
      set value of variable indigoSensor to val
   end tell
end writeVar

on roundThis(n, numDecimals)
   set multiplier to 10 ^ numDecimals
   n * multiplier
   round result
   result / multiplier
end roundThis

If I round off the number with the roundThis script first then have Indigo write the value to a variable it still won't round it off to two decimal places.

Code: Select all

set val to 99.897896875578

set val to my roundThis(val, 2)

--return val ==> returns rounded off value correctly

writeVar("test123_", val)

on writeVar(indigoSensor, val)
   tell application "IndigoServer"
      set value of variable indigoSensor to val
   end tell
end writeVar


on roundThis(n, numDecimals)
   set multiplier to 10 ^ numDecimals
   n * multiplier
   round result
   result / multiplier
end roundThis

[matt (support)]

I'm not sure. I don't understand your 2 examples -- why is writeVar defined twice, but roundThis isn't defined in the 2nd example?

Matt,

OK if you run this first script, the variable "test123_" val is written to the Indigo Variable List as 99.09999999999999. If you run the second script to see what the rounded off number is, it is rounded off to 99.1. Why is Indigo changing the rounded off 99.1 to 99.09999999999999?

Code: Select all

set val to 99.09792092097

tell application "IndigoServer"
   set val to my (roundThis(val, 2))
   set value of variable "test123_" to val
end tell

on roundThis(n, numDecimals)
   set multiplier to 10 ^ numDecimals
   n * multiplier
   round result
   result / multiplier
end roundThis

Code: Select all

roundThis(99.09792092097, 2)

on roundThis(n, numDecimals)
   set multiplier to 10 ^ numDecimals
   n * multiplier
   round result
   result / multiplier
end roundThis

[matt (support)]

Indigo isn't changing the rounding. The problem is that floating point numbers can not represent 99.1 exactly. See this article for an explanation.

The solution is to format the number as a string with a specific precision. Off the top of my head I'm not sure how to do that in AppleScript, but in python it would be:

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>>> valueAsStr = "%0.1f" % (99.09792092097,)
>>> valueAsStr
'99.1'

Matt,

I change to this (added "as string") and it is now OK.

thanks.

Code: Select all

set val to my (roundThis(val, 2)) as string

Bob... can you post your entire script? I'm trying to get some visual feedback on airfoil speaker volumes. The come in anywhere between 0 and 1... I'm hoping to be able to round to the nearest .1.

Bob... can you post your entire script? I'm trying to get some visual feedback on airfoil speaker volumes. The come in anywhere between 0 and 1... I'm hoping to be able to round to the nearest .1.

Hi. I don't know what Bob's script is like, but it's possible to use AppleScript to round to any specific decimal place. For example:

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(round (0.853953 * 10) rounding as taught in school) / 10

which will return

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0.9

There are other rounding algorithms if you don't like the statistical aversion to zero inherent to the "rounding as taught in school" method. There's also "rounding up", "rounding down", "rounding to nearest", and "rounding toward zero". Don't forget that Indigo variables can only contain values of type "text" or "string", so if you have an Indigo variable that contains this example 0.853953 value, you'll first have to convert that text into a number.

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set anAppleScriptVariable to (value of variable "Your_Variable_Name") as number

That will ensure that the "anAppleScriptVariable" is a number rather than a text string. In my experience, it's not necessary to convert the number back to a string when assigning it to an Indigo variable as Indigo (or perhaps the OS's AppleScript interpreter) seems to do this automatically upon assigning a number to the Indigo variable.

Bob... can you post your entire script? I'm trying to get some visual feedback on airfoil speaker volumes. The come in anywhere between 0 and 1... I'm hoping to be able to round to the nearest .1.

I have an audio control page that includes volume up and down controls for Airfoil. I wanted increments of 10, from 0 to 100 for the volume levels, so I implemented rounding and a multiplier of 100 when keeping track of the current Airfoil volume level, so that I could always set it explicitly with any volume change:

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tell application "IndigoServer"
   set the value of variable "airfoilVolume" to (round ((zoneVolume + 0.1) * 100))
end tell

Based on the currently selected audio zone, I get the current speaker volume from Airfoil, increment or decrement it by .1 (or set it to 0 or 1 if I reach either end of the scale), and then round and store the number in Indigo as above. I display the value stored in Indigo on the control page.

Hello All,
I am trying to round a variable "testVar" from 75.1 to 75 and when I attempt the following:

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tell application "IndigoServer"
   set the value of variable "testVar" to round (testVar)
end tell

I get "The variable testVar is not defined.
What's the blinding flash of the obvious that I am missing?

Thanks,
~Lou

Hello All,
I am trying to round a variable "testVar" from 75.1 to 75 and when I attempt the following:

Code: Select all

tell application "IndigoServer"
   set the value of variable "testVar" to round (testVar)
end tell

I get "The variable testVar is not defined.
What's the blinding flash of the obvious that I am missing?

Thanks,
~Lou

"testVar" and testVar aren't the same thing (note the quotes) so the unquoted variable testVar isn't defined. But if you change round (testVar) to round ("testVar") you'll get an error that Applescript "can't make "testVar" into type real." The following code, however, will do the trick:

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tell application "IndigoServer"
   set a to value of variable "testVar"
   set the value of variable "testVar" to round (a)
end tell

Cheers,
Dave

Hello All,
I am trying to round a variable "testVar" from 75.1 to 75 and when I attempt the following:

Code: Select all

tell application "IndigoServer"
   set the value of variable "testVar" to round (testVar)
end tell

I get "The variable testVar is not defined.
What's the blinding flash of the obvious that I am missing?

Thanks,
~Lou

"testVar" and testVar aren't the same thing (note the quotes) so the unquoted variable testVar isn't defined. But if you change round (testVar) to round ("testVar") you'll get an error that Applescript "can't make "testVar" into type real." The following code, however, will do the trick:

Code: Select all

tell application "IndigoServer"
   set a to value of variable "testVar"
   set the value of variable "testVar" to round (a)
end tell

Cheers,
Dave

Dave,
That did the trick exactly! Thank you. I think I recall reading somewhere that it's better to use python since python uses IDs rather than names and a variable name could change while the ID will always stay the same. Could you or someone else provide the complimentary code is say the variable ID for testVar is "87654321"? As I learn a little here and there I want to be as tidy as possible

Thanks again,
~Lou

Glad I can help. Indigo stores values as strings so we might need to do some converting. Here is the Python version of the same process, with some added things you might do (or not) as needed:

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a = indigo.variables[362195049].value # Get the value from the variable.
a = float(a) # Let's try to see if the value will float.
a = round(a) # Rounds the value.
a = int(a) # Converts the value to an integer.
a = str(a) # Converts the value back into a string.
indigo.variable.updateValue(362195049, a) # Write the updated value back to Indigo

It gets a little more complicated because Python becomes unhappy if it can't complete a step, so the code might bomb for something you're trying to do. It's also important to note that you won't need all of these steps for every conversion.

Post back if you have any questions.
Dave