hour

Hour component of input date and time

Syntax

h = hour(t)

Description

h = hour(t) returns the hour component for each date and time specified in t.

The h output is a double array and contains integer values from 0 to 23. To assign values to the hour component of values in t, use t.Hour and modify the Hour property.

Examples

Find Hour Number of Datetime Values

t = datetime('today'):hours(8):datetime('tomorrow');
t.Format = 'MMM dd, HH:mm'

t = 1×4 datetime
   Apr 19, 00:00   Apr 19, 08:00   Apr 19, 16:00   Apr 20, 00:00

h = hour(t)

h = 1×4

     0     8    16     0

Input Arguments

t — Input date and time

datetime array

Input date and time, specified as a datetime array.

To support existing code that previously required Financial Toolbox™, hour also accepts serial date numbers and text as inputs, but they are not recommended. For more information, see Version History.

Extended Capabilities

Tall Arrays

Calculate with arrays that have more rows than fit in memory.

The hour function fully supports tall arrays. For more information, see Tall Arrays.

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• In generated code, this function supports only datetime arrays as inputs. You cannot specify serial date numbers or text as inputs in generated code.

GPU Code Generation

Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

Refer to the usage notes and limitations in the C/C++ Code Generation section. The same usage notes and limitations apply to GPU code generation.

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

The hour function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

The hour function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced in R2014b

R2022a: Serial date number and text inputs not recommended

Although hour supports serial date number and text inputs, datetime values are recommended instead. The datetime data type provides flexible date and time formats, storage out to nanosecond precision, and properties to account for time zones and daylight saving time.

To convert serial date numbers or text to datetime values, use the datetime function. For example:

t = datetime(738427.656845093,"ConvertFrom","datenum");
h = hour(t)

h =

    15

There are no plans to remove support for serial date number or text inputs.

R2022a: hour functions from Financial Toolbox and MATLAB combined

In previous releases, there were two hour functions: one in MATLAB^® that accepted datetime values, and one in Financial Toolbox that accepted serial date numbers or text values. As of R2022a, you can call hour without Financial Toolbox. When you call hour from MATLAB, it accepts all previous input types.

For example, you can make these calls with a serial date number and text from MATLAB:

h = hour(738427.656845093)

h =

    15

h = hour("2021/09/28 15:45:51.4160")

h =

    15

In addition, hour accepts a second input for the date format when the first input is not a datetime array:

h = hour(t,F)

In this syntax, specify F using a valid date format as documented for the datestr function, though 'Q' format specifiers are not supported. For example:

h = hour("2021/09/28 15:45:51.4160","yyyy/dd/mm hh:MM:ss.fff")

h =

    15