Description
Return one basE91 symbol's zero-based alphabet index.
Encoded representations separate alphabet symbols, numerical digit values, byte grouping and tail padding. Recognizing one symbol or pad-bit pattern is not full payload decoding, and different alphabet variants can assign different values.
Return one basE91 symbol's zero-based alphabet index.
When to use this tool
Use Base91 Alphabet Symbol Index when inspecting one stated alphabet, group or padding component.
How to use the tool and how it works
- Enter symbol. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read index. Use the output convention below.
Return one basE91 symbol's zero-based alphabet index. Require one symbol from the implementation's ordered alphabet of letters, digits and punctuation.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| symbol | One symbol from the stated alphabet; matching uses the stated case convention. | Required. Text; maximum UTF-16 length 8192. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| index | Position under the stated indexing convention; inspect any missing-value sentinel. | Required. Safe integer. |
{
"input": {
"symbol": "A"
},
"output": {
"index": 0
}
}Limitations and assumptions
- Other Base91 variants may differ; this does not decode grouped data or validate a complete payload.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Alternative or Complementary methods
Use the complete codec matching the required alphabet and canonicality rules for real encoded data.
References
Similar or alternative tools
- RFC 4648 Alphabet Symbol Index
Look up one symbol in a selected RFC 4648 alphabet.
- Decoding: Base64 Alphabet Symbol Value
Return a Base64 or Base64url symbol's value.