Struct HourFn 

pub struct HourFn;

Extracts the hour component (0 to 23) from a time or datetime serial.

Remarks

• For values >= 1, only the fractional time part is used.
• For values < 1, the value is treated directly as a time fraction.
• Date-system choice does not affect hour extraction because only the fractional part is used.

Examples

title: "Extract hour from noon"
formula: "=HOUR(0.5)"
expected: 12

title: "Extract hour from datetime serial"
formula: "=HOUR(45351.75)"
expected: 18

related:
  - MINUTE
  - SECOND
  - TIME
faq:
  - q: "Why is HOUR unchanged across 1900 and 1904 date systems?"
    a: "HOUR reads only the fractional time component of a serial, so date-system epoch differences do not affect it."

Trait Implementations

impl Debug for HourFn

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Function for HourFn

[formualizer-docgen:schema:start] Name: HOUR Type: HourFn Min args: 1 Max args: 1 Variadic: false Signature: HOUR(arg1: number@scalar) Arg schema: arg1{kinds=number,required=true,shape=scalar,by_ref=false,coercion=NumberLenientText,max=None,repeating=None,default=false} Caps: PURE [formualizer-docgen:schema:end]

fn caps(&self) -> FnCaps

Capability flags for this function

fn name(&self) -> &'static str

fn min_args(&self) -> usize

fn arg_schema(&self) -> &'static [ArgSchema]

fn eval<'a, 'b, 'c>( &self, args: &'c [ArgumentHandle<'a, 'b>], _ctx: &dyn FunctionContext<'b>, ) -> Result<CalcValue<'b>, ExcelError>

The unified evaluation path.

fn namespace(&self) -> &'static str

fn variadic(&self) -> bool

fn volatile(&self) -> bool

fn aliases(&self) -> &'static [&'static str]

Optional list of additional alias names (case-insensitive) that should resolve to this function. Default: empty slice. Implementors can override to expose legacy names. Returned slice must have ’static lifetime (typically a static array reference).

fn function_salt(&self) -> u64

fn eval_reference<'a, 'b, 'c>( &self, _args: &'c [ArgumentHandle<'a, 'b>], _ctx: &dyn FunctionContext<'b>, ) -> Option<Result<ReferenceType, ExcelError>>

Optional reference result path. Only called by the interpreter/engine when the callsite expects a reference (e.g., range combinators, by-ref argument positions, or spill sources).

fn dispatch<'a, 'b, 'c>( &self, args: &'c [ArgumentHandle<'a, 'b>], ctx: &dyn FunctionContext<'b>, ) -> Result<CalcValue<'b>, ExcelError>

Dispatch to the unified evaluation path with automatic argument validation.