`second` — Extract second components from datetime values with MATLAB-compatible output shapes.

second extracts the seconds component from datetime scalars or arrays and returns doubles with the same shape as the input. Fractional seconds are preserved when sub-second precision exists.

Syntax

X = second(t)

Inputs

Name	Type	Required	Default	Description
`value`	`Any`	Yes	—	Datetime input.

Returns

Name	Type	Description
`X`	`Any`	Numeric scalar/tensor result.

Errors

Identifier	When	Message
`RunMat:datetime:InvalidArgument`	Arguments or option grammar do not match supported datetime forms.	`datetime: invalid argument`
`RunMat:datetime:InvalidInput`	Input values cannot be parsed/converted/broadcast to a valid datetime result.	`datetime: invalid input`
`RunMat:datetime:Internal`	Internal datetime state or indexing/evaluation failed unexpectedly.	`datetime: internal operation failed`

How `second` works

second(t) accepts datetime scalars and datetime arrays.
The output shape matches the input shape.
Returned values are doubles so fractional seconds can be represented.
Passing a non-datetime value raises a datetime-specific error.

Does RunMat run `second` on the GPU?

second does not dispatch GPU kernels; it extracts the second component from CPU-side datetime objects.

GPU memory and residency

No. second reads datetime objects on the CPU and returns ordinary host-side numeric arrays.

Examples

Extract whole seconds from a scalar datetime

t = datetime(2024, 4, 9, 13, 30, 5);
s = second(t)

Expected output:

s = 5

Preserve fractional seconds

t = datetime(2024, 4, 9, 13, 30, 5.25);
s = second(t)

Expected output:

s = 5.2500

Using `second` with coding agents

Open a RunMat example with live inputs, then ask the agent to explain how second changes the result.

Run a small second example, explain the result, then change one input and compare the output.

FAQ

Can second return fractional values?⌄

Yes. RunMat preserves fractional seconds and returns them as doubles.

Does second preserve the input shape?⌄

Yes. The numeric output has the same size as the input datetime array.

Does second run on the GPU?⌄

No. datetime values are host-side objects, so second executes on the CPU.

datetime · day · duration · hour · minute · month · year

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how second is executed, line by line, in Rust.

View the source for second in Rust on GitHub
Learn how the RunMat runtime works
Found a bug? Open an issue with a minimal reproduction.

About RunMat

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second — Extract second components from datetime values with MATLAB-compatible output shapes.