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datenum

(Not recommended; use datetime or duration ) Convert date and time to serial date number

datenum is not recommended. To represent points in time, use datetime arrays. To represent elapsed times, use duration or calendarDuration arrays. For more information on updating your code, see Version History or Replace Discouraged Instances of Serial Date Numbers and Date Strings .

Syntax


            
             DateNumber = datenum(t)


            
             DateNumber = datenum(DateString)


            
             DateNumber = datenum(DateString,formatIn)


            
             DateNumber = datenum(DateString,PivotYear)


            
             DateNumber = datenum(DateString,formatIn,PivotYear)


            
             DateNumber = datenum(DateVector)


            
             DateNumber = datenum(Y,M,D)


            
             DateNumber = datenum(Y,M,D,H,MN,S)

Description

DateNumber = datenum( t ) converts the datetime or duration values in the input array t to serial date numbers.

A serial date number represents the whole and fractional number of days from a fixed, preset date (January 0, 0000) in the proleptic ISO calendar.

example

DateNumber = datenum( DateString ) converts text representing dates and times to serial date numbers. If the format used in the text is known, specify the format as formatIn . Syntaxes without formatIn are significantly slower than syntaxes that include it.

DateNumber = datenum( DateString , formatIn ) uses formatIn to interpret the dates and times represented by DateString .

example

DateNumber = datenum( DateString , PivotYear ) uses PivotYear to interpret text that specifies the year as two characters. If the format used in the text is known, specify the format as formatIn . Syntaxes without formatIn are significantly slower than syntaxes that include it.

DateNumber = datenum( DateString , formatIn , PivotYear ) uses formatIn to interpret the dates and times represented by DateString , and PivotYear to interpret text that specifies the year as two characters. You can specify formatIn and PivotYear in either order.

example

DateNumber = datenum( DateVector ) converts date vectors to serial date numbers, and returns a column vector of m date numbers, where m is the total number of date vectors in DateVector .

example

DateNumber = datenum( Y,M,D ) returns the serial date numbers for corresponding elements of the Y , M , and D (year, month, day) arrays. The arrays must be of the same size (or any can be a scalar). You also can specify the input arguments as a date vector, [Y,M,D] .

example

DateNumber = datenum( Y,M,D,H,MN,S ) additionally returns the serial date numbers for corresponding elements of the H , MN , and S (hour, minute, and second) arrays. The arrays must be of the same size (or any can be a scalar). You also can specify the input arguments as a date vector, [Y,M,D,H,MN,S] .

Examples

collapse all

Convert datetime Array to Date Numbers

Open Live Script

format long 
t = [datetime('now');datetime('tomorrow')]

t = 2x1 datetime
   23-Jan-2025 01:19:25
   24-Jan-2025 00:00:00

DateNumber = datenum(t)

DateNumber = 2×1
10⁵ ×
   7.396400551544395
   7.396410000000000

Convert Text Representing Date to Date Number

Open Live Script

DateString = '19-May-2001';
formatIn = 'dd-mmm-yyyy';
datenum(DateString,formatIn)

ans = 
730990

datenum returns a date number for text representing a date with the format 'dd-mmm-yyyy' .

Convert Text with Multiple Dates to Date Numbers

Open Live Script

Pass several dates as character vectors in a cell array. All input dates must use the same format.

DateString = {'09/16/2007';'05/14/1996';'11/29/2010'};
formatIn = 'mm/dd/yyyy';
datenum(DateString,formatIn)

Convert Text Representing Date to Date Number Using Pivot Year

Open Live Script

Convert text representing a date to a serial date number using the default pivot year.

n = datenum('12-jun-17','dd-mmm-yy')

n = 
736858

The text that represents this date number is '12-Jun-2017' .

Convert the same text to a serial date number using 1400 as the pivot year.

n = datenum('12-jun-17','dd-mmm-yy',1400)

n = 
517712

The text that represents this date number is '12-Jun-1417' .

Convert Date Vector to Date Number

Open Live Script

datenum([2009,4,2,11,7,18])

ans = 
7.3387e+05

Convert Year, Month, and Day to Date Number

Open Live Script

Convert a date specified by year, month and day values to a serial date number.

n = datenum(2001,12,19)

n = 
731204

Input Arguments

collapse all

`t` — Dates and times
array of `datetime` or `duration` values

Dates and times, specified as an array of datetime or duration values. The datenum function does not account for time zone information in t and does not adjust datetime values that occur during Daylight Saving Time. That is, datenum treats the TimeZone property of datetime arrays as empty and converts the remaining date and time information to a serial date number.

If any element of t is a NaT or NaN , then the corresponding value returned by datenum is a NaN . If any element of t is Inf or -Inf , then the corresponding value returned by datenum is Inf or -Inf .

Data Types: datetime | duration

`DateVector` — Date vectors
matrix

Date vectors, specified as an m -by-6 or m -by-3 matrix containing m full or partial date vectors, respectively. A full date vector has six elements, specifying year, month, day, hour, minute, and second, in that order. A partial date vector has three elements, specifying year, month, and day, in that order. Each element of DateVector must be a positive or negative integer value except for the seconds element, which can be fractional. If an element falls outside the conventional range, datenum adjusts both that date vector element and the previous element. For example, if the minutes element is 70 , then datenum adjusts the hours element by 1 and sets the minutes element to 10 . If the minutes element is - 15 , then datevec decreases the hours element by 1 and sets the minutes element to 45 . Month values are an exception. The datenum function sets month values less than 1 to

If any element of DateVector is a NaT or NaN , then the corresponding value returned by datenum is a NaN . If any element of DateVector is Inf or -Inf , then the corresponding value returned by datenum is Inf or -Inf .

Example: [2003,10,24,12,45,07]

Data Types: double

`DateString` — Text representing dates and times
character array | cell vector of character vectors | string vector

Text representing dates and times, specified as a character array where each row contains text representing one point in time, as a cell vector of character vectors, or as a string vector. All rows of a character array, or all elements of a cell vector or string vector, must have the same format.

Example: '24-Oct-2003 12:45:07'

Example: ['19-Sep-2013';'20-Sep-2013';'21-Sep-2013']

Example: {'15-Oct-2010' '20-Nov-2012'}

If the format used in the text is known, you should also specify formatIn . If you do not specify formatIn , then DateString must be in one of the following formats.

Format of Text Representing Dates and Times	Example
`'dd-mmm-yyyy HH:MM:SS'`	`01-Mar-2000 15:45:17`
`'dd-mmm-yyyy'`	`01-Mar-2000`
`'mm/dd/yyyy'`	`03/01/2000`
`'mm/dd/yy'`	`03/01/00`
`'mm/dd'`	`03/01`
`'mmm.dd,yyyy HH:MM:SS'`	`Mar.01,2000 15:45:17`
`'mmm.dd,yyyy'`	`Mar.01,2000`
`'yyyy-mm-dd HH:MM:SS'`	`2000-03-01 15:45:17`
`'yyyy-mm-dd'`	`2000-03-01`
`'yyyy/mm/dd'`	`2000/03/01`
`'HH:MM:SS'`	`15:45:17`
`'HH:MM:SS PM'`	`3:45:17 PM`
`'HH:MM'`	`15:45`
`'HH:MM PM'`	`3:45 PM`

Note

The symbolic identifiers describing date and time formats are different from those that describe the display formats of datetime arrays.

Certain formats might not contain enough information to convert text representations of dates and times. In those cases, hours, minutes, and seconds default to 0, days default to 1, months default to January, and years default to the current year. datevec and datenum consider two-character years (e.g., '79' ) to fall within the 100-year range centered around the current year.

When you do not specify formatIn , note the following:

For the formats that specify the month as two digits ( mm ), the month value must not be greater than 12.
However, for the format 'mm/dd/yy' , if the first entry in the text is greater than 12 and the second entry is less than or equal to 12, then datenum considers the text to be in 'yy/mm/dd' format.

`formatIn` — Format of input text representing dates and times
character vector | string scalar

Format of the input text representing dates and times, specified as a character vector or string scalar of symbolic identifiers.

Example: 'dddd, mmm dd, yyyy'

The following table shows symbolic identifiers that you can use to construct the formatIn character vector. You can include characters such as a hyphen, space, or colon to separate the fields.

Note

The symbolic identifiers describing date and time formats are different from the identifiers that describe the display formats of datetime arrays.

Symbolic Identifier	Description	Example
`yyyy`	Year in full	`1990` , `2002`
`yy`	Year in two digits	`90` , `02`
`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 one or two digits	`3` , `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 one or two digits	`5` , `20`
`d`	Day using capitalized first letter	`M` , `T`
`HH`	Hour in two digits (no leading zeros when symbolic identifier `AM` or `PM` is used)	`05` , `AM`
`MM`	Minute in two digits	`12` , `02`
`SS`	Second in two digits	`07` , `59`
`FFF`	Millisecond in three digits	`057`
`AM or PM`	`AM` or `PM` inserted in text representing time	`3:45:02` The `formatIn` value must follow these guidelines: You cannot specify any field more than once. For example, you cannot use `'yy-mmm-dd-m'` because it has two month identifiers. The one exception to this is that you can combine one instance of `dd` with one instance of any of the other day identifiers. For example, `'dddd mmm dd yyyy'` is a valid input. When you use `AM` or `PM` , the `HH` field is also required. You only can use `QQ` alone or with a year specifier. `PivotYear` — Start year of 100-year date range present minus 50 years (default) \| integer Start year of the 100-year date range in which a two-character year resides, specified as an integer. Use a pivot year to interpret dates that specify the year as two characters. If `formatIn` contains the time of day, the pivot year is computed from the current time of the current day, month, and year. Otherwise it is computed from midnight of the current day, month, and year. Example: `2000` Note If the input date format specifies a four-character year, then the last two characters are truncated, and the first two characters specify the year. For example, if the date and pivot year are specified as `('25122015','ddmmyyyy',2000)` , then the resulting date is `25-12-2020` , not `25-12-2015` . Data Types: `double` `Y,M,D` — Year, month, and day arrays numeric arrays Year, month, and day arrays specified as numeric arrays. These arrays must be the same size, or any one can be a scalar. The values in `Y,M,D` must be integer values. If `Y,M,D` are all scalars or all column vectors, you can specify the input arguments as a date vector, `[Y,M,D]` . Example: `2003,10,24` Data Types: `double` `Y,M,D,H,MN,S` — Year, month, day, hour, minute, and second arrays numeric arrays Year, month, day, hour, minute, and second arrays specified as numeric arrays. These arrays must be the same size, or any one can be a scalar. `datenum` does not accept milliseconds as a separate input, but as a fractional part of the seconds input, `S` . The values in `Y,M,D,H,MN` must be integer values. If `Y,M,D,H,MN,S` are all scalars or all column vectors, you can specify the input arguments as a date vector, `[Y,M,D,H,MN,S]` . Example: `2003,10,24,12,45,07.451` Data Types: `double` Output Arguments collapse all `DateNumber` — Serial date numbers scalar \| vector Serial date numbers, returned as a column vector of length `m` , where `m` is the total number of input date vectors or character vectors representing dates and times. Tips To create arbitrarily shaped output, use the `datenum(Y,M,D)` and `datenum(Y,M,D,H,MN,S)` syntaxes. The `datenum(DateVector)` syntax creates only a column vector of date numbers. datenum(2013,[1 3; 2 4],ones(2,2)) ans = 735235 735294 735266 735325 Extended Capabilities Tall Arrays Calculate with arrays that have more rows than fit in memory. The `datenum` function fully supports tall arrays. For more information, see Tall Arrays . Thread-Based Environment Run code in the background using MATLAB® `backgroundPool` or accelerate code with Parallel Computing Toolbox™ `ThreadPool` . This 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™. This function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox) . Version History Introduced before R2006a expand all R2022b: Not recommended There are no plans to remove `datenum` . However, the `datetime` , `duration` , and `calendarDuration` data types 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. MATLAB ^® functions that accept serial date numbers as inputs also accept `datetime` arrays as inputs. To convert a serial date number to a `datetime` value, call `datetime` with the `ConvertFrom` name-value argument set to `"datenum"` . d = 738522; d = datetime(d,"ConvertFrom","datenum") d = datetime 01-Jan-2022 See Also `datetime` \| `datevec` Topics Represent Dates and Times in MATLAB Carryover in Date Vectors and Strings You clicked a link that corresponds to this MATLAB command: Run the command by entering it in the MATLAB Command Window. Web browsers do not support MATLAB commands.

datenum

Syntax

Description

Examples

Convert datetime Array to Date Numbers

Convert Text Representing Date to Date Number

Convert Text with Multiple Dates to Date Numbers

Convert Text Representing Date to Date Number Using Pivot Year

Convert Date Vector to Date Number

Convert Year, Month, and Day to Date Number

Input Arguments

`t` — Dates and times
array of `datetime` or `duration` values

`DateVector` — Date vectors
matrix

`DateString` — Text representing dates and times
character array | cell vector of character vectors | string vector

`formatIn` — Format of input text representing dates and times
character vector | string scalar

`PivotYear` — Start year of 100-year date range
present minus 50 years (default) | integer

`Y,M,D` — Year, month, and day arrays
numeric arrays

`Y,M,D,H,MN,S` — Year, month, day, hour, minute, and second arrays
numeric arrays

Output Arguments

`DateNumber` — Serial date numbers
scalar | vector

Tips

Extended Capabilities

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

Thread-Based Environment
Run code in the background using MATLAB® `backgroundPool` or accelerate code with Parallel Computing Toolbox™ `ThreadPool` .

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

Version History

R2022b: Not recommended

See Also

Topics

datenum (adsbygoogle = window.adsbygoogle || []).push({});

Syntax

Description

Examples

Convert datetime Array to Date Numbers

Convert Text Representing Date to Date Number

Convert Text with Multiple Dates to Date Numbers

Convert Text Representing Date to Date Number Using Pivot Year

Convert Date Vector to Date Number

Convert Year, Month, and Day to Date Number

Input Arguments

t — Dates and times array of datetime or duration values

DateVector — Date vectors matrix

DateString — Text representing dates and times character array | cell vector of character vectors | string vector

formatIn — Format of input text representing dates and times character vector | string scalar

PivotYear — Start year of 100-year date range present minus 50 years (default) | integer

Y,M,D — Year, month, and day arrays numeric arrays

Y,M,D,H,MN,S — Year, month, day, hour, minute, and second arrays numeric arrays

Output Arguments

DateNumber — Serial date numbers scalar | vector

Tips

Extended Capabilities

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

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

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

Version History

R2022b: Not recommended

See Also

Topics

datenum

`t` — Dates and times
array of `datetime` or `duration` values

`DateVector` — Date vectors
matrix

`DateString` — Text representing dates and times
character array | cell vector of character vectors | string vector

`formatIn` — Format of input text representing dates and times
character vector | string scalar

`PivotYear` — Start year of 100-year date range
present minus 50 years (default) | integer

`Y,M,D` — Year, month, and day arrays
numeric arrays

`Y,M,D,H,MN,S` — Year, month, day, hour, minute, and second arrays
numeric arrays

`DateNumber` — Serial date numbers
scalar | vector

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

Thread-Based Environment
Run code in the background using MATLAB® `backgroundPool` or accelerate code with Parallel Computing Toolbox™ `ThreadPool` .

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