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dateshift

Shift date or generate sequence of dates and times

Description

example

t2 = dateshift(t,'start',unit) shifts each value in the datetime array t back to the beginning of the unit of time specified by unit. The output t2 is the same size as t.

For example, if you shift 9:14 a.m., June 27, 2021 to the start of the hour, then the shifted value is 9:00 a.m., June 17, 2021. If you shift it to the start of the month, then the shifted value is 12:00 a.m., June 1, 2021.

example

t2 = dateshift(t,'end',unit) shifts the values ahead to the end of the unit of time specified by unit.

  • The end of a day, hour, minute, or second is also the beginning of the next day, hour, minute, or second. For example, if you shift 9:14 a.m., June 27, 2021 to the end of the hour, then the shifted value is 10:00 a.m., June 17, 2021.

  • The end of a year, quarter, month, or week is midnight at the beginning of the last day of that year, quarter, month, or week. For example, if you shift 9:14 a.m., June 17, 2021 to the end of the month, then the shifted value is 12:00 a.m., June 30, 2021.

example

t2 = dateshift(t,'dayofweek',dow) shifts to the specified day of the week that occurs on or after each datetime value in array t. If a date in t already falls on the specified day of the week, then dateshift returns the same date.

example

t2 = dateshift(t,'dayofweek','weekend') shifts to the weekend day (either Saturday or Sunday) that occurs on or after each datetime value in array t.

example

t2 = dateshift(t,'dayofweek','weekday') shifts to the weekday (Monday–Friday) that occurs on or after each datetime value in array t.

example

t2 = dateshift(___,rule) shifts each value in array t according to the pattern specified by rule. You can use this syntax with any of the arguments in the previous syntaxes.

Examples

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Create a datetime value with the current date.

t = datetime('today')
t = datetime
   01-Sep-2021

Shift the date to the start of the year.

t2 = dateshift(t,'start','year')
t2 = datetime
   01-Jan-2021

Create a datetime value with the current date.

t = datetime('today')
t = datetime
   01-Sep-2021

Shift the date to the end of the same month.

t2 = dateshift(t,'end','month')
t2 = datetime
   30-Sep-2021

Create a datetime value.

t = datetime('today')
t = datetime
   01-Sep-2021

Shift the date to the start of the next month.

t2 = dateshift(t,'start','month','next')
t2 = datetime
   01-Oct-2021

Shift the date to the end of the next month.

t3 = dateshift(t,'end','month','next')
t3 = datetime
   31-Oct-2021

Create a datetime array. Format it to display day of the week and the date.

Shift an array of dates forward to the next Friday.

t = [datetime(2014,08,03) datetime(2014,04,15)];
t.Format = 'eeee, dd MMM yyyy'
t = 1x2 datetime
   Sunday, 03 Aug 2014    Tuesday, 15 Apr 2014

Shift the dates forward to the next Friday.

t2 = dateshift(t,'dayofweek','Friday')
t2 = 1x2 datetime
   Friday, 08 Aug 2014   Friday, 18 Apr 2014

Shift the dates backward to the previous Monday.

t3 = dateshift(t,'dayofweek','Monday','previous')
t3 = 1x2 datetime
   Monday, 28 Jul 2014   Monday, 14 Apr 2014

Create a datetime array. Format it to display day of the week and the date.

t = [datetime(2021,5,30) datetime(2021,6,4)];
t.Format = 'eeee, dd MMM yyyy'
t = 1x2 datetime
   Sunday, 30 May 2021   Friday, 04 Jun 2021

Shift to the first weekend day that occurs on or after each value in t. Because Sunday is already a weekend day, the first datetime value is not shifted. But the second value shifts from Friday to Saturday.

t2 = dateshift(t,'dayofweek','weekend')
t2 = 1x2 datetime
   Sunday, 30 May 2021     Saturday, 05 Jun 2021

Create a datetime array. Format it to display day of the week and the date.

t = [datetime(2021,5,30) datetime(2021,6,4)];
t.Format = 'eeee, dd MMM yyyy'
t = 1x2 datetime
   Sunday, 30 May 2021   Friday, 04 Jun 2021

Shift to the first weekday that occurs on or after each value in t. Sunday shifts to Monday. But because Friday is already a weekday, the second datetime value is not shifted.

t2 = dateshift(t,'dayofweek','weekday')
t2 = 1x2 datetime
   Monday, 31 May 2021   Friday, 04 Jun 2021

Find the date that falls at the end of the fifth week from today.

t = datetime('today');
t.Format = 'eeee, dd MMM yyyy'
t = datetime
   Wednesday, 01 Sep 2021

t2 = dateshift(t,'end','week',5)
t2 = datetime
   Saturday, 09 Oct 2021

Generate a sequence of dates consisting of the next three occurrences of Friday.

t = datetime('today')
t = datetime
   01-Sep-2021

t2 = dateshift(t,'dayofweek','Friday',1:3)
t2 = 1x3 datetime
   03-Sep-2021   10-Sep-2021   17-Sep-2021

Input Arguments

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Input date and time, specified as a datetime array.

Unit of time, specified as one of these values:

  • 'year'

  • 'quarter'

  • 'month'

  • 'week'

  • 'day'

  • 'hour'

  • 'minute'

  • 'second'

Example: t2 = dateshift(t,'start','hour')

Example: t2 = dateshift(t,'end','month')

Name or number for a day of the week, specified as a string scalar or character vector that is a localized day name or an integer between 17.

Integers between 17 correspond to days of the week, as shown in the table.

1

Sunday

2

Monday

3

Tuesday

4

Wednesday

5

Thursday

6

Friday

7

Saturday

Example: t2 = dateshift(t,'dayofweek','Sunday')

Example: t2 = dateshift(t,'dayofweek',1)

Rule for shifting datetime values, specified as 'next', 'previous', 'nearest', 'current', a scalar integer, or an array of integers.

The table describes the rules for shifting datetime values.

RuleDescription

'next'

Shift datetime value to next unit of time or specified day of week.

Note: This rule is the default rule for the 'dayofweek' input argument.

'previous'

Shift datetime value to previous unit of time or specified day of week.

'nearest'

Shift datetime value to nearest occurrence of the unit of time or specified day of week.

You can use this rule to round datetime values.

'current'

Shift datetime value within the current unit of time or to the specified day within the current week.

Note: This rule is the default rule for the 'start' and 'end' input arguments.

1

Equivalent to the 'next' rule.

n, where n > 1

Equivalent to the 'next' rule applied n times.

0

Equivalent to the 'current' rule.

-1

Equivalent to the 'previous' rule.

-n, where n > 1

Equivalent to the 'previous' rule applied n times.

Array of integers

Shifts each value in t according to the rule specified by the corresponding integer in rule.

The input arguments t and rule must have the same size or one of them must be scalar.

Behavior When datetime Values Match 'dayofweek' Argument

If you specify 'dayofweek' and t contains datetime values that fall on the specified day of the week, then dateshift treats those datetime values as the next or previous occurrences of the specified day of the week.

For example, dateshift(datetime(2015,12,24),'dayofweek','Thursday',rule) returns a datetime value with a date of December 24, 2015 if rule is 'next', 'previous', 'nearest', 1, or -1, because December 24, 2015 is a Thursday.

Extended Capabilities

See Also

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Introduced in R2014b