Premise

In PowerApps we can mask/hide the entire text of a textbox control by changing its Mode to Password. However, in this post I’ll demonstrate how to mask the first ‘X’ characters and only display the last 4 characters, like Credit Card or, Bank Account numbers.

Solution

Following is the formula to mask the first ‘X’ characters of a control except the last 4 digit, in PowerApps.

Concatenate(Concat(ForAll(Split(Left(Parent.Default, (Len(Parent.Default) - 4)),""), "X"), Value), Right(Parent.Default, 4))

The above code snippet can be described as the following:

• I’m using this control inside a PowerApps form. Hence, my source value is coming from, Parent.Default.
• First we extracted all the characters from the original value, Parent.Default, excluding the last 4 digit, using the PowerApps Left function.
  

  Left(Parent.Default, (Len(Parent.Default) - 4))

• Then I’m passing the extracted text to the Split function.
  

  Split(Left(Parent.Default, (Len(Parent.Default) - 4)),"")

• Split will convert the string to array/collection of each character.
• Then I’m passing this collection to the ForAll function.
• ForAll will loop over each character of the extracted string and replace the same with the character, ‘X’. We can also use any character here. For ex, ‘*’, ‘#’, etc.
  

  ForAll(Split(Left(Parent.Default, (Len(Parent.Default) - 4)),""), "X")

• Once, I’ve replaced all the values of my collection with the character ‘X’, I’ll join this collection as a single string using the Concat function.
  

  Concat(ForAll(Split(Left(Parent.Default, (Len(Parent.Default) - 4)),""), "X"), Value)

• Now that I have successfully masked the first ‘X’ characters, I also need to extract the last 4 characters as is i.e., without masking. This can be easily achieved using the Right function.
  

  Right(Parent.Default, 4)

• Finally, the 2 strings, masked and normal, can be joined using the Concatenate function.

Concatenate(
    Concat(
        ForAll(
            Split(
                Left(Parent.Default, (Len(Parent.Default) - 4)),""),
             "X"), 
        Value), 
    Right(Parent.Default, 4))

Key Takeaway

• As I’m using my label control inside a PowerApps forms, the source value is coming from, Parent.Default. If you have any other source then, do replace this with your actual source.