datetime — Create datetime arrays from text, components, or serial date numbers and interoperate with MATLAB date/time helper functions.

datetime constructs datetime objects from component values, text inputs, and serial date-number forms. Supported creation paths, Format display behavior, elapsed-duration arithmetic, calendar-duration arithmetic, legacy serial-date helpers, and common business-day helpers follow current MATLAB/RunMat datetime semantics.

Syntax

t = datetime()
t = datetime(textOrArray)
t = datetime(serialDateNumbers)
t = datetime(year, month, day)
t = datetime(year, month, day, hour)
t = datetime(year, month, day, hour, minute)

t = datetime()
t = datetime(textOrArray)
t = datetime(serialDateNumbers)
t = datetime(year, month, day)
t = datetime(year, month, day, hour)
t = datetime(year, month, day, hour, minute)
t = datetime(year, month, day, hour, minute, second)
t = datetime(serialDateNumbers, "ConvertFrom", "datenum")
t = datetime(___, "Format", format)
t = datetime(textOrArray, "InputFormat", inputFormat)
t = datetime(___, Name, Value, ...)

Inputs

Returns

Errors

How datetime works

• datetime() with no arguments returns the current local date and time.
• datetime(Y, M, D) and datetime(Y, M, D, H, MN, S) construct datetimes from numeric components. Scalar inputs expand to match non-scalar component arrays.
• datetime(text) accepts string scalars, string arrays, and character vectors. Supported text includes common ISO-like forms, dd-MMM-yyyy forms, and now.
• datetime(serials, 'ConvertFrom', 'datenum') interprets numeric values as MATLAB serial date numbers.
• datetime(serials) also accepts raw serial date numbers for the current implementation, producing datetime values directly from those serials.
• The Format property controls text rendering. Assigning t.Format = 'yyyy-MM-dd HH:mm:ss' updates how the object displays without changing the stored point in time.
• Linear indexing t(k) is supported and returns datetime values.
• Comparison operators and plus/minus day arithmetic are supported. Subtracting two datetime values returns numeric day deltas.
• now, today, and clock expose current local time in MATLAB-compatible serial, datetime, and date-vector forms.
• datenum, datevec, datestr, weekday, eomday, etime, and isbetween cover common legacy serial-date conversion, formatting, query, and interval operations.
• datetime + calendarDuration and datetime - calendarDuration apply month-aware calendar arithmetic with end-of-month clamping.
• isbusday, holidays, busdays, days252bus, daysdif, fbusdate, and lbusdate provide weekday plus market-holiday business-calendar compatibility for standard scripts. Custom weekend definitions and all Financial Toolbox option forms are not yet implemented.

Does RunMat run datetime on the GPU?

datetime does not allocate GPU objects or invoke provider kernels. If a numeric input originates on the GPU, RunMat gathers it before building the datetime object.

GPU memory and residency

No. RunMat represents datetime values as host-side objects with an internal serial-date tensor and a Format property. Even when the constructor receives gathered numeric data, the resulting object remains resident on the CPU.

Examples

Constructing a scalar datetime from numeric components

t = datetime(2024, 4, 9, 13, 30, 0)

Expected output:

t =
  09-Apr-2024 13:30:00

Parsing text into datetimes

t = datetime(["2024-04-09 13:30:00"; "2024-04-10 08:15:00"])

Expected output:

t =
09-Apr-2024 13:30:00
10-Apr-2024 08:15:00

Creating datetimes from serial date numbers

d = datetime([739351; 739352], 'ConvertFrom', 'datenum')

Expected output:

d =
09-Apr-2024 00:00:00
10-Apr-2024 00:00:00

Changing display format without changing the stored value

t = datetime(2024, 4, 9, 13, 30, 0);
t.Format = 'yyyy-MM-dd HH:mm:ss';
disp(t)

Expected output:

2024-04-09 13:30:00

Extracting calendar and clock components

t = datetime(2024, 4, 9, 13, 30, 5);
y = year(t)
m = month(t)
d = day(t)
h = hour(t)

Expected output:

y = 2024
m = 4
d = 9
h = 13

Adding days and subtracting datetimes

t0 = datetime(2024, 4, 9);
t1 = t0 + 7;
delta = t1 - t0

Expected output:

delta = 7

Using serial-date conversion helpers

n = datenum(2024, 4, 9);
v = datevec(n);
s = datestr(n, 'yyyy-MM-dd')

Expected output:

s =
  2024-04-09

Adding a calendar month clamps at month end

t = datetime(2024, 1, 31, 'Format', 'yyyy-MM-dd');
t + calmonths(1)

Expected output:

ans =
  2024-02-29

Using datetime with coding agents

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

FAQ

Related Datetime functions

Open-source implementation

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

• View the source for datetime 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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