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datenum

Convert date and time to serial date number

Syntax

  • DateNumber = datenum(DateString)
  • DateNumber = datenum(DateString,formatIn) example
  • DateNumber = datenum(DateString,PivotYear)
  • DateNumber = datenum(DateString,formatIn,PivotYear) example
  • DateNumber = datenum(DateVector) example
  • DateNumber = datenum(Y,M,D) example
  • DateNumber = datenum(Y,M,D,H,MN,S)

Description

example

DateNumber = datenum(t) converts the datetime values in datetime 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).

DateNumber = datenum(DateString) converts date strings to serial date numbers. If the date string format is known, use formatIn. Syntaxes without formatIn are significantly slower than those that include it.

example

DateNumber = datenum(DateString,formatIn) uses formatIn to interpret each date string.

DateNumber = datenum(DateString,PivotYear) uses PivotYear to interpret date strings that specify the year as two characters. If the date string format is known, use formatIn. Syntaxes without formatIn are significantly slower than those that include it.

example

DateNumber = datenum(DateString,formatIn,PivotYear) uses formatIn to interpret each date string, and PivotYear to interpret date strings that specify 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].

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

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Convert datetime Array to Date Numbers

format long

t = [datetime('now');datetime('tomorrow')]
DateNumber = datenum(t)
t = 

   19-Sep-2014 23:52:01
   20-Sep-2014 00:00:00


DateNumber =

   1.0e+05 *

   7.358619944627379
   7.358620000000000

Convert Date String to Date Number

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

      730990

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

Convert Multiple Date Strings to Date Numbers

Pass multiple date strings in a cell array. All input date strings must use the same format.

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

      733301
      729159
      734471

Convert Date String to Date Number Using Pivot Year

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

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

      736858

The corresponding date string to this date number is 12-Jun-2017.

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

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

      517712

The corresponding date string to this date number is 12-Jun-1417.

Convert Date Vector to Date Number

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

   7.3387e+05

Convert Year, Month, and Day to Date Number

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

n = datenum(2001,12,19)
n =

      731204

Input Arguments

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tdatetime valuesscalar | vector | matrix | multidimensional array

datetime values, specified as a scalar, vector, matrix, or multidimensional datetime array. datenum 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 t as empty and converts the remaining date and time information to a serial date number.

DateVector — Date vectorsmatrix

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 should be a positive or negative integer value with the exception of 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, 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. datenum sets month values less than 1 to 1.

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

Data Types: double

DateString — Date stringsstring | character array | 1–D cell array of strings

Date strings, specified as a character array where each row corresponds to one date string, or as a one dimensional cell array of strings. All of the date strings 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 date string format is known, you should also specify formatIn. If you do not specify formatIn, DateString must be in one of the following formats.

Date String Format

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 string formats are different from those that describe the display formats of datetime arrays.

Certain date string formats might not contain enough information to convert the date string. 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 date string 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 date string is greater than 12 and the second entry is less than or equal to 12, then datenum considers the date string to be in 'yy/mm/dd' format.

formatIn — Format of the input date stringstring

Format of the input date string, specified as a string of symbolic identifiers.

Example: 'dddd, mmm dd, yyyy'

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

    Note:   The symbolic identifiers describing date string formats are different from those 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 two digits

03, 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

05, 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, 5 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 date string

3:45:02 PM

The formatIn string 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 rangepresent 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 date strings 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

Data Types: double

Y,M,D — Year, month, and day arraysscalar | vector | matrix | array

Year, month, and day arrays specified as a scalar, vector, matrix or array. These must be the same size, or any one can be a scalar. Y,M,D should 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 arraysscalar | vector | matrix | array

Year, month, day, hour, minute and second arrays specified as a scalar, vector, matrix or array. These 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. Y,M,D,H,MN should 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

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DateNumber — Serial date numbersscalar | vector

Serial date numbers, returned as a column vector of length m, where m is the total number of input date vectors or date strings.

More About

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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

See Also

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