day — Extract day-of-month numbers from datetime values.
day extracts the day-of-month from a datetime scalar or array and returns the result as doubles with the same shape as the input.
How day works
day(t)accepts datetime scalars and datetime arrays.- The output shape matches the input shape.
- Day values reflect the calendar day stored in the datetime object.
- Passing a non-datetime value raises a datetime-specific error.
How RunMat runs day on the GPU
day does not dispatch GPU kernels; it extracts the day component from CPU-side datetime objects.
GPU memory and residency
No. day reads datetime objects on the CPU and returns ordinary host-side numeric arrays.
Examples
Extract the day from a scalar datetime
t = datetime(2024, 4, 9, 13, 30, 0);
d = day(t)Expected output:
d = 9Extract days from a datetime array
t = datetime([2024 2025], [1 6], [15 20]);
d = day(t)Expected output:
d =
15 20FAQ
What day does day return?⌄
It returns the calendar day-of-month, such as 9 for April 9.
Does day preserve the input shape?⌄
Yes. The numeric output has the same size as the input datetime array.
Does day run on the GPU?⌄
No. datetime values are host-side objects, so day executes on the CPU.
Related Datetime functions
Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how day works, line by line, in Rust.
- View day.rs on GitHub
- Learn how the runtime works
- Found a bug? Open an issue with a minimal reproduction.
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