Fetch unique 3 character code

RE: Fetch unique 3 character code

Stefan Helzle — Wed, 01 Jan 2025 10:59:37 GMT

You need a recursive expression. I created the helper function

a!localVariables(
  local!newQuotient: floor(ri!quotient / 26),
  local!newRemainders: append(
    ri!remainders,
    mod(ri!quotient, 26)
  ),
  if(
    local!newQuotient > 0,
    rule!SSH_DecTo26Helper(
      quotient: local!newQuotient,
      remainders: local!newRemainders
    ),
    local!newRemainders
  )
)

And call it like this

index(
  char(enumerate(26) + 65),
  rule!SSH_DecTo26Helper(
    quotient: ri!value,
    remainders: {}
  ) + 1
)

Line 2 represents the characters A..Z. The "+1" shifts the numbers from 0..25 to 1..26. ri!value is an integer. In your case this would be the integer primary key generated in the database.

RE: Fetch unique 3 character code

shivas3219 — Tue, 31 Dec 2024 22:48:28 GMT

ri!input is 3 char code e.g "WXY" and ri!iterationCount is number of codes i need. i have given input as "WXY" but it generated wrong codes

RE: Fetch unique 3 character code

shivas3219 — Tue, 31 Dec 2024 22:45:56 GMT

Stefan Helzle I have below code but its not working in every case

a!localVariables(
  local!splitByArray: char(code(ri!input)),
  local!convertedToBase26: tointeger(rule!SS_getIdByAlphabet(local!splitByArray[1])) * power(26, 2) + 
  tointeger(rule!SS_getIdByAlphabet(local!splitByArray[2])) * power(26, 1) + 
  tointeger(rule!SS_getIdByAlphabet(local!splitByArray[3])) * power(26, 0),
  local!listOfGettableNumbers: tointeger(local!convertedToBase26) + enumerate(ri!iterationCount) + 1,
  local!setOfCodes: a!forEach(
    items: tointeger(local!listOfGettableNumbers),
    expression: a!localVariables(
      local!thirdCharacter: rule!SS_getAlphabetById(tointeger(mod(fv!item, 26))),
      local!secondCharacter: rule!SS_getAlphabetById(
        tointeger(mod(rounddown(fv!item / 26, 0), 26))
      ),
      local!divisionResult: rounddown(rounddown(fv!item / 26, 0) / 26, 0),
      local!firstCharacter: rule!SS_getAlphabetById(
        rounddown(mod(local!divisionResult, 26), 0)
      ),
      concat(
        local!firstCharacter,
        local!secondCharacter,
        local!thirdCharacter
      )
    )
  ),
  local!setOfCodes
)

RE: Fetch unique 3 character code

shivas3219 — Tue, 31 Dec 2024 20:51:57 GMT

Stefan Helzle Thank you very much. I will try this method.

RE: Fetch unique 3 character code

Stefan Helzle — Tue, 31 Dec 2024 10:16:17 GMT

Did you consider to let the database create the integer primary key, and then derive your alphabet code from this? Then you are sure to never have any duplicates. This needs a transformation from the decimal numeric system into a system based on the number 26. You can then store this code in a separate field.

I general I doubt that this is a good design decision, but that's up to you to decide.

For the implementation, you might want to use the reduce() function. Check my blog post for how to implement such algorithms in Appian: appian.rocks/.../

I asked GPT for how to do that:

To transform a number from the decimal system (base 10) into a numeric system using the letters A-Z (which can be interpreted as a base-26 system), you can follow these steps:

1. **Understand the Mapping**: In this system, you can map the numbers as follows:
- 1 = A
- 2 = B
- 3 = C
- ...
- 26 = Z
- 27 = AA
- 28 = AB
- and so on.

2. **Conversion Process**:
- Subtract 1 from the decimal number to adjust for zero-based indexing.
- Divide the number by 26.
- The remainder will give you the letter (0 corresponds to A, 1 to B, ..., 25 to Z).
- Continue dividing the quotient by 26 until it reaches 0.
- Collect the letters in reverse order.

### Example:
Let's convert the decimal number 28 to this system.

1. **Initial Number**: 28
2. **Subtract 1**: 28 - 1 = 27
3. **Divide by 26**:
- 27 ÷ 26 = 1 (Quotient)
- Remainder = 27 % 26 = 1 (which corresponds to A)
4. **Next Step**:
- Now take the quotient (1).
- 1 - 1 = 0 (stop here since the quotient is now 0).
- 0 ÷ 26 = 0 (Quotient)
- Remainder = 0 % 26 = 0 (which corresponds to A)
5. **Collect Letters**: The letters collected are A (from the last step) and A (from the first step), so we read them in reverse order: AA.

Thus, the decimal number 28 is represented as "AB" in this system.

### Another Example:
Convert 703 to this system.

1. **Initial Number**: 703
2. **Subtract 1**: 703 - 1 = 702
3. **Divide by 26**:
- 702 ÷ 26 = 27 (Quotient)
- Remainder = 702 % 26 = 0 (which corresponds to A)
4. **Next Step**:
- 27 - 1 = 26
- 26 ÷ 26 = 1 (Quotient)
- Remainder = 26 % 26 = 0 (which corresponds to A)
5. **Next Step**:
- 1 - 1 = 0 (stop here).
- 0 ÷ 26 = 0 (Quotient)
- Remainder = 0 % 26 = 0 (which corresponds to A)
6. **Collect Letters**: The letters collected are A (from the last step), A (from the second step), and A (from the first step), so we read them in reverse order: AAA.

Thus, the decimal number 703 is represented as "AAA" in this system.

Feel free to provide a specific decimal number if you want me to convert it for you!

RE: Fetch unique 3 character code

shivas3219 — Tue, 31 Dec 2024 09:08:26 GMT

Stefan Helzle could you please suggest how to get number of unique codes I need, using above design gives me values till AAZ, but I need further codes for my requirement

RE: Fetch unique 3 character code

Stefan Helzle — Mon, 30 Dec 2024 20:19:51 GMT

Well ... then, good luck with this design.

RE: Fetch unique 3 character code

shivas3219 — Mon, 30 Dec 2024 19:44:45 GMT

There will be only user who would be updating it for now. I agree that it may create some conflicting values with multiple users. This code is being used in mapping to other tables.

RE: Fetch unique 3 character code

Stefan Helzle — Mon, 30 Dec 2024 19:21:53 GMT

Sorry, but this will generate conflicting values as soon as multiple users create rows. There is a good reason for why we use the database to create these values.

For what purpose do you need these values? And why not just use the numeric primary key values from the database?

RE: Fetch unique 3 character code

shivas3219 — Mon, 30 Dec 2024 19:05:37 GMT

Stefan Helzle This is not a primary key but unique code to identify the record and some other stuff. I would have created a dictionary of unique 3 char code but it may degrade performance.

RE: Fetch unique 3 character code

venkatrea696188 — Mon, 30 Dec 2024 18:51:51 GMT

[quote userid="252725" url="~/discussions/f/rules/38233/fetch-unique-3-character-code/143964"]it saves in database with generated unique code in a column[/quote]

In this case we can suggest multiple approaches. The approach you mentioned , I don't suggest it for various reasons .

One would be incremental number (simple approach).
Generating UUID
Or appending timestamp to a Application prefix or something like that(It's going to be unique every time) , the list goes on

RE: Fetch unique 3 character code

Stefan Helzle — Mon, 30 Dec 2024 18:49:09 GMT

Are you sure this is a good way to solve the problem of primary key values?

RE: Fetch unique 3 character code

shivas3219 — Mon, 30 Dec 2024 18:30:38 GMT

When i add new records to the editable grid, it saves in database with generated unique code in a column. If i create 3 new rows, it needs 3 new codes to be generated to assign it to each row. There may situations where end user can delete already added row and at that time we need to recreate codes and assign to each row accordingly.

RE: Fetch unique 3 character code

venkatrea696188 — Mon, 30 Dec 2024 18:25:47 GMT

Yup it's gonna give you that .I just pasted sample code how it needs be done

[quote userid="21957" url="~/discussions/f/rules/38233/fetch-unique-3-character-code/143960"]Very curious as to why you would need to do this[/quote]

Same here ,Can I know why you need this in the first place . We can suggest alternatives

RE: Fetch unique 3 character code

shivas3219 — Mon, 30 Dec 2024 17:32:14 GMT

Thanks all for the response. If i pass "AAZ" and 2. its returning "AA[" and "AA\" where it should be "ABA" and "ABB"

RE: Fetch unique 3 character code

Mathieu Drouin — Mon, 30 Dec 2024 14:59:23 GMT

Random != Unique.

Very curious as to why you would need to do this but here is some code to generate a string variable length with random characters. Not unique though. You should look into UUIDs if you want to achieve this.

a!localVariables(
  local!character: "A",
  local!numberOfCharactersToAppend: 2,
  local!allCharacters: "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
  local!charactersToAppend: a!forEach(
    items: enumerate(local!numberOfCharactersToAppend),
    expression: a!localVariables(
      local!randomIndex: rounddown((rand() * 26 + 1), 0),
      mid(
        local!allCharacters,
        local!randomIndex,
        1
      )
    )
  ),
  concat(
    local!character,
    joinarray(local!charactersToAppend, "")
  )
)

RE: Fetch unique 3 character code

venkatrea696188 — Mon, 30 Dec 2024 11:52:48 GMT

Couple of questions , where you intended to use this and the limit of iteration count ?? This you can write using Code and char function .

Pasting a Sample code for your reference , You need to change the code if the iteration count is more than 25

a!localVariables(
  local!inputcodes: if(
    a!isNullOrEmpty(ri!input),
    null,
    code(ri!input)
  ),
  local!iterate: a!forEach(
    items: enumerate(ri!iterationCount+1),
    expression: a!localVariables(
      local!index:fv!item,
    concat(
      char(local!inputcodes[1]),
      char(local!inputcodes[2]),
      char(local!inputcodes[3] + local!index)
    ))
  ),
  local!iterate
)