{ "category": "Operators", "display_name": "Percentage (%)", "entry_kind": "built_in_operator", "eval_api": { "method": "POST", "url": "https://handbook.dnacalc.com/api/eval" }, "function_id": "FUNC.OP_PERCENT", "implementation_state": { "answer_bank": null, "detail": "", "dnacalc_commit": "9e1884369a678158dd82d3d74188daf986995e87", "in_catalogue": true, "state": "unmeasured", "state_label": "Implemented, no recorded answers attributed to it", "summary": "Implemented; no recorded answers are attributed to this entry", "workbook_corpus": null }, "implementations": [ { "commit": "9e1884369a678158dd82d3d74188daf986995e87", "flavour": "excel-compatibility-candidate", "language": "Rust", "name": "CalcFunc", "own_code": [ "https://github.com/DnaCalc/DnaCalc/blob/9e1884369a678158dd82d3d74188daf986995e87/crates/calc-func/src/catalogue/arithmetic.rs#L45-L45", "https://github.com/DnaCalc/DnaCalc/blob/9e1884369a678158dd82d3d74188daf986995e87/crates/calc-func/src/catalogue/arithmetic.rs#L199-L211" ], "repository": "https://github.com/DnaCalc/DnaCalc", "shared_code": [ "catalogue/arithmetic::divide", "catalogue/arithmetic::flushed", "catalogue/arithmetic::binary", "catalogue/arithmetic::operands" ], "source": "https://github.com/DnaCalc/DnaCalc/blob/9e1884369a678158dd82d3d74188daf986995e87/crates/calc-func/src/catalogue/arithmetic.rs#L45-L45", "state": "unmeasured", "suite": null, "summary": "Implemented; no recorded answers are attributed to this entry" } ], "json_url": "https://handbook.dnacalc.com/api/functions/FUNC.OP_PERCENT.json", "name": "OP_PERCENT", "notes": [], "schema": "efh.function-reference/v1", "section_order": [ "what-it-does", "try-it", "quirks", "how-to-implement", "version-differences", "alternatives" ], "sections": { "alternatives": "\n### Relationships\n\n\n- [`FUNC.OP_DIVIDE`](FUNC.OP_DIVIDE.md) and [`FUNC.OP_MULTIPLY`](FUNC.OP_MULTIPLY.md) — the\n two operators `%` might be implemented in terms of, and the reason the ambiguity above\n matters.\n- [`FUNC.OP_NEGATE`](FUNC.OP_NEGATE.md), [`FUNC.OP_UNARY_PLUS`](FUNC.OP_UNARY_PLUS.md) — the\n other unary members of the family.\n- `PERCENTILE`, `PERCENTRANK`, `PERCENTOF` — statistical functions whose names share the word\n and share nothing else.\n- `TEXT(x, \"0%\")` — the formatting route. If the goal is display, `%`-the-operator is the\n wrong tool; if the goal is arithmetic, the format is.\n\n\n", "how-to-implement": "\n### Notes for implementers\n\n\n- Pick a spelling and record which one: `x / 100` or `x * 0.01`. They are not the same\n function of a double, and a compatibility implementation that guesses will disagree with\n Excel on some operands. The Handbook cannot yet tell you which to pick.\n- Do not implement `%` by string manipulation of the formula or by adjusting the cell format.\n It is a value transformation.\n- Chained application (`A%%`) must scale twice; there is no idempotence to exploit.\n- The elementwise array path must preserve element-local failures.\n\n\n", "quirks": "\n### Result and edge cases\n\n- **Text and logical operands.** Shared to-number rules from\n [coercion and lifting](../model/02-coercion-and-lifting.md). Note the overlap: chapter 02\n records that Excel's text-to-number recognizer itself accepts percent signs in some\n locale-dependent forms, so `\"50%\"` as *text* may already convert to `0.5` before this\n operator is reached — and `\"50%\"%` would then scale it again. That interaction is\n unrecorded here and is a good probe.\n- **Empty and omitted.** Per-family policy under chapter 02; unrecorded for this row.\n- **Arrays.** `CoercionLiftProfile::UnaryNumericScalarOrArrayElementwise` — mapped\n elementwise, with element-local failures.\n- **Underflow.** Scaling a subnormal by a hundredth flushes it toward zero; scaling any tiny\n value repeatedly reaches zero. Nothing about this is specific to `%`, but `%` is a cheap way\n to reach the subnormal range from ordinary-looking data.\n- **Overflow.** Not reachable: scaling down cannot overflow.\n\n\n", "sources": "- `data/presence/FUNC.OP_PERCENT.json` — implementing module\n `earlier-implementation/operator_arithmetic_family.rs`.\n- Handbook `content/model/01-value-universe.md` (numbers wearing formats),\n `02-coercion-and-lifting.md` (the locale-dependent recognizer note),\n `03-call-pipeline.md`.\n\n\n", "version-differences": "No comparison between specific Excel builds is recorded here yet. This does not establish that all builds behave alike.", "what-it-does": "\n`A%` converts its operand to a number and returns that number scaled by one hundredth. `50%`\nis `0.5`; `A1%` is a hundredth of whatever `A1` holds.\n\nThe interesting content is in the word \"scaled\", because binary64 gives two inequivalent\nspellings of it:\n\n- `x / 100` — divide by an exactly representable integer, one rounding.\n- `x * 0.01` — multiply by the double nearest to one hundredth, which is *not* one hundredth,\n and then round.\n\nThese do not agree for every `x`. The literal `0.01` is already a rounded approximation, so\nthe multiplication rounds twice in effect; the division rounds once against an exact divisor\nand is the more accurate of the two. For most operands both spellings land on the same\ndouble, and for some they do not — which makes this a real, if small, last-bit question about\na function whose definition looks trivial.\n\nThe percent *format* is a separate thing entirely. Formatting a cell as a percentage changes\nhow a number is displayed and how typed input is interpreted by the host; `%` as an operator\nchanges the value. A cell holding `0.5` formatted as a percentage shows `50%` without this\noperator ever running. Chapter 01's rule applies: dates, currency and percentages are numbers\nwearing formats.\n\n\n\n### Arguments\n\n\n| Position | Name | Meaning |\n|---|---|---|\n| 0 | `A` | The operand to scale. Required. |\n\nArity is exactly 1; no optional arguments, no defaults. The operator is postfix — it follows\nits operand — which makes it the only member of the arithmetic family with that shape.\n\nPostfix position raises a precedence question (`-2%`, `2^3%`, `2%%`) that this Handbook does\nnot answer: formula grammar and precedence are explicitly out of scope (`CHARTER.md` section\n4), and the operator-inventory decision register in the sources records precedence ownership\nas an open item. What the Handbook *can* say is that `%` is a one-argument function of a\nvalue, and that chaining it (`A%%`) applies it twice.\n\n\n" }, "signature": { "display": "number%", "parameters": [ { "description": null, "name": "number", "optional": false, "repeats": false } ], "trailing_repeats": false }, "sources": { "metadata": { "admission": { "label": "implemented", "reason": null }, "arity": { "max": 1, "min": 1 }, "category": "Operators", "classification": { "arg_preparation_profile": "ValuesOnlyPreAdapter", "coercion_lift_profile": "UnaryNumericScalarOrArrayElementwise", "determinism_class": "Deterministic", "error_collapse_profile": "None", "fec_dependency_profile": "None", "host_interaction_class": "None", "kernel_signature_class": "NumToNum", "rich_value_usage": "RichBlind", "surface_fec_dependency_profile": "RefOnly", "thread_safety_class": "SafePure", "volatility_class": "NonVolatile" }, "descriptions": { "long": null, "short": null, "short_source": "no-short-description" }, "docs": null, "entry_kind": "built_in_operator", "localized_family_names": null, "localized_names": [], "signature": { "display": "number%", "parameters": [ { "description": null, "name": "number", "optional": false, "repeats": false } ], "trailing_repeats": false }, "surface_name": "OP_PERCENT", "version_marker": null, "xlcall": null }, "microsoft": null }, "try_it": { "formula": "=25%" }, "url": "https://handbook.dnacalc.com/functions/OP_PERCENT.html", "variants": [], "versions": [] }