Converting Binary to Integers in Power Apps

But… why?

I promise there are legitimate reasons why you might have to work with binary integers in Power Apps and that’ll be more obvious near the end of this series which should probably be titled “Doing low level operations in Power Apps for masochists”. For now, know it’s possible and if you need to do it here’s the guide.

Let’s do it!

Converting binary values (as text) to their numeric values is “relatively” straight-forward (at least for this series). There are a bunch of guides on how to convert from base 2 to base 10 conceptually and if you’re interested in all the details, go check em out! For our purposes, here’s a basic overview (don’t weep hardcore computer scientists):

A Brief but Boring Background of Some Binary Stuff

Binary digits (1 or 0) indicate if the value it represents is “on” or “off”. In this case, “on” (1) means that value should be included when calculating the result. The values start with 1 and double each time so that the values are 1, 2, 4, 8, 16… etc. to whatever “size” for the data type (read right to left):

As you can see from the image above, the values (1,2,4,8,16…) are really just increasing powers of 2. We’re going to use that fact to our advantage.

So to convert binary to a number, add the values to each other whenever there’s a 1 in the corresponding positions.

The Actual Expression

I went all out in my Canvas Power Apps design skills and created the following screen:

I’ve got a textbox called txtFromBinary and a label under Result that is set to a variable called intResult

Here’s the contents of the OnSelect for the button:

ClearCollect(binaryToInt,[]);
With({
input: txtFromBinary.Text
},
ForAll(Sequence(Len(input)),
With({
binaryDigit: Right(Left(input,Len(input)-(Value-1)),1) //Grab the right most digit
},
Collect(binaryToInt,{
binaryDigit: binaryDigit, //Not necessary (debug)
value:If(binaryDigit = "1", Power(2,Value-1), 0), //Not necessary (debug)
runningTotal:If(binaryDigit = "1", Power(2,Value-1), 0) + If(Value=1, 0, Last(binaryToInt).runningTotal)
})
)
)
);
Set(intResult,Last(binaryToInt).runningTotal);

Let’s look at what’s happening line by line:

  • Line 1 – We are using a temporary collection (binaryToInt) to store intermediate results as we process the binary text character by character. So, we clear it out before starting.
  • Lines 2-4 – Using the With function we can setup a local variable called input which we can reference rather than the Text Input’s Value each time (and it gets cleaned up at the end)
  • Line 5 – We start a ForAll loop against an arbitrary collection we generate with Sequence.
    • We’re going to see this combination over and over in this series because this is Power Apps’ janky version of a for loop. In this case, we are using it to let us run through a collection that is exactly as long as our binary string (which we get by using the Len function). This makes working with each individual character one at a time possible.
  • Lines 6-8 – Again using the With function (which I absolutely love) we setup a local variable. This time we’re extracting the exact character, binaryDigit, we want to work with.
    • In their infinite wisdom, Power Apps didn’t feel the need to implement a substring function so we’ve got an overly complicated combination of Right and Left to grab a single character. The exact character is determined by the use of the Value keyword which in this case references the number from the Sequence function we used earlier.
  • Line 9 – We are calculating a running total of the final value but there’s no way to set results from within a ForAll. Fortunately, you can call Collect within a ForAll so we’re doing exactly that and storing our calculations as we go.
  • Line 10 – This is just for debugging and isn’t used at all but helps us verify we pulled the right bit
  • Line 11 – Also just for debugging, it helps us identify that we calculated the positional value correctly
  • Line 12 – This is the actual calculation where we are adding 2 numbers together.
    • The first is the positional value for a bit which is 0 when the bit is “off” (0) and calculated as a Power of 2 when “on” (1). We use the Value keyword which references the number from the Sequence function used earlier. However, we have to subtract one because Sequence starts with 1 (rather than 0).
    • The second number is the running total we’ve been calculating on the previous bits. We get this by using the Last function to pull in our most recently added item in the collection (the last iteration of the loop) unless this is the first iteration (Value=1) in which case it’s just 0.
  • Line 17 – Since we were calculating as we went, we know that the very last value of our temporary collection is the final result. So we grab it and set it to a global variable to be referenced in our label.

Looking in our temporary collection, binaryToInt might make it a little easier to understand:

Or maybe it didn’t?! Oh well!

The good news is that it works – so copy and paste as you please. And for those of you who can’t get enough of doing things in Power Apps that were not intended to be done in Power Apps, be sure to come back for Part 2: Converting Integers to Binary in Power Apps!

2 thoughts on “Converting Binary to Integers in Power Apps

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