> For the complete documentation index, see [llms.txt](https://nelson-9.gitbook.io/nelson/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nelson-9.gitbook.io/nelson/markdown/en/time/datenum.md).

# datenum

Return the date/time input as a serial day number.

## 📝 Syntax

* d = datetnum(datevec)
* d = datenum(datestr)
* d = datenum(datestr, format)
* d = datenum(datestr, pivotYear)
* d = datenum(DateString,format,pivotYear)
* d = datetnum(Y, M, D)
* d = datetnum(Y, M, D, H, MN, S)

## 📥 Input argument

* datevec - a vector: \[Y, M, D, H, MN, S] or matrix N x 6.
* format - a string specifying the date format, or leave it empty (' ') for automatic format detection.
* datestr - a string, cell of string or string array: text representing a date.
* Y, M, D, H, MN, S - double: Year, Month, Day, Hours, Minutes, Secondes (scalar or vector).
* pivotYear: Start year of 100-year date range - integer value or present minus 50 years (default).

## 📤 Output argument

* d - a double: serial date number (serial day 1 corresponds to 1-Jan-0000).

## 📄 Description

d = datenum() returns the serial date number corresponding to current date.

d = datenum(datevec) converts date vector to serial date number.

d = datenum(datestr) andd = datenum(datestr, format) converts string to serial date number.

Supported format conversion:

dd-mmm-yyyy HH:MM:SS 10-Mar-2010 16:48:17

dd-mmm-yyyy 10-Mar-2010

mm/dd/yyyy 03/10/2010

mm/dd/yy 03/10/00

mm/dd 03/10

mmm.dd,yyyy HH:MM:SS Mar.10,2010 16:48:17

mmm.dd,yyyy Mar.10,2010

yyyy-mm-dd HH:MM:SS 2010-03-10 16:48:17

yyyy-mm-dd 2010-03-10

yyyy/mm/dd 2000/03/10

HH:MM:SS 16:48:17

HH:MM:SS PM 3:48:17 PM

HH:MM 16:48

HH:MM PM 3:35 PM

If format is not specified, the default format isdd-mmm-yyyy.

If format is specified and not using predefined format, the format must be specified as a character vector or string scalar composed of symbolic identifiers.

The format of the input text for representing dates and times, expressed as a character vector or string scalar composed of symbolic identifiers.

| Symbolic Identifier | Description                                                                     | Example         |
| ------------------- | ------------------------------------------------------------------------------- | --------------- |
| yyyy                | Year in full                                                                    | 1995, 2012      |
| yy                  | Year in two digits                                                              | 89, 01          |
| QQ                  | Quarter year using letter Q and one digit                                       | Q1              |
| mmmm                | Month using full name                                                           | March, December |
| mmm                 | Month using first three letters                                                 | Mar, Dec        |
| mm                  | Month in two digits                                                             | 04, 12          |
| m                   | Month using capitalized first letter                                            | M, D            |
| dddd                | Day using full name                                                             | Monday, Tuesday |
| ddd                 | Day using first three letters                                                   | Mon, Tue        |
| dd                  | Day in two digits                                                               | 06, 21          |
| d                   | Day using capitalized first letter                                              | M, T            |
| HH                  | Hour in two digits (no leading zeros when symbolic identifier AM or PM is used) | 06, 6 AM        |
| MM                  | Minute in two digits                                                            | 11, 01          |
| SS                  | Second in two digits                                                            | 06, 59          |
| FFF                 | Millisecond in three digits                                                     | 056             |
| AM or PM            | AM or PM inserted in text representing time                                     | 5:46:02 PM      |

## 💡 Example

```matlab

d = datenum([1973,8,4,12,1,18])
datevec(d)
d = datenum('04–Aug-1973 12:01:18')
d = datenum(["04–Aug-1973 12:01:18"; "04–Aug-1974 11:01:18"])

```

## 🔗 See also

[datevec](/nelson/markdown/en/time/datevec.md).

## 🕔 History

| Version                | 📄 Description                |
| ---------------------- | ----------------------------- |
| 1.0.0                  | initial version               |
| 1.8.0                  | date string parsing extended. |
| 1.10.0                 | added: format '               |
| ' means try to detect. |                               |