Day (Property)

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Range of dates
Managing the days and months
Handling the durations
Operators available for the days
Calculating the last day of the month
Calculating a 90-day end-of-month due date
Calculating the end of a 30-day period
Calculations on dates

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Day (Property)

In french: Jour

The Day property is used to:

Get the day from a Date or DateTime variable, or get the number of days from a Duration variable.
Change the day in a Date or DateTime variable, or change the number of days in a Duration variable.
Get the day or the number of days from a Date item (in "Date", "Date and Time" or "Duration" format).
Not available.
Change the day or the number of days in a Date item (in "Date", "Date and Time" or "Duration" format).
Not available.

Remark: The Day property is used to easily change dates (add a day, etc).

Reminder: Date items are used to manage:

"Year - Month - Day" dates (YYYYMMDD format).
"Year - Month - Day - Hours - Minutes - Seconds - Milliseconds" dates and times (YYYYMMDDHHmmSSCCC format).
"Number of days - Number of hours - Number of minutes - Number of seconds - Number of milliseconds" durations (+DHHMMSSCCC format).

Versions 17 and later

This property is now available for iPhone/iPad applications.

New in version 17

This property is now available for iPhone/iPad applications.

Versions 20 and later

This property is now available in browser code for the Date, DateTime or Duration variables.

New in version 20

This property is now available in browser code for the Date, DateTime or Duration variables.

Versions 21 and later

This property is now available in Apple Watch mode.

This property is now available in Universal Windows 10 App mode.

New in version 21

This property is now available in Apple Watch mode.

This property is now available in Universal Windows 10 App mode.

This property is now available in Apple Watch mode.

This property is now available in Universal Windows 10 App mode.

Example

// Example on a variable
StartDate is Date = "20011225"
// Add 5 days to the date
StartDate.Day += 5
// Modify the days
StartDate.Day = 10

// Example on an item
Work.StartDate = "20011225"
// Add 5 days to the date
Work.StartDate.Day += 5
// Modify the days
Work.StartDate.Day = 10

Syntax

Finding out the day in a Date, DateTime or Duration variable Hide the details

<Result> = <Date>.Day

<Result>: Integer

Day on 2 digits.

<Date>: Date or DateTime

Name of the variable of type Date, DateTime or Duration to be used.

Modifying the day in a Date, DateTime or Duration variable Hide the details

<Date>: Date or DateTime

Name of the variable of type Date, DateTime or Duration to be used.

<New day>: Integer or character string

New day in digits (included between 1 and 31). Replaces the day in the specified date.

Not available in browser code and in PHP

Finding out the day in a Date item Hide the details

<Result> = <Data file>.<Item>.Day

<Result>: Integer

Day on 2 digits.

<Data file>: Character string

Name of the data file used. This name was defined in the data model editor or with the File Description type.

<Item>: Character string

Name of the item used. This name was defined in the data model editor or with the Item Description type.

Not available in browser code and in PHP

Modifying the day in a Date item Hide the details

<Data file>: Character string

Name of the data file used. This name was defined in the data model editor or with the File Description type.

<Item>: Character string

Name of the item used. This name was defined in the data model editor or with the Item Description type.

<New day>: Integer or character string

New day in digits (included between 1 and 31). Replaces the day in the specified date.

Remarks

Range of dates

The Date and DateTime types are used to manage the dates from 01/01/0001 to 31/12/9999.

Managing the days and months

Case 1: Direct assignment
During a direct assignment (for example, MyDay.Day = n), the day must be included between 1 and 31. A WLanguage error occurs if the specified day is incorrect.
The following syntax MyDay.Day = MyDay.Day + 5 may generate an error at runtime. For example, the following lines of code trigger an error:

// Code triggering the error
MyDate is Date = "20201126" // 11/26/2020
MyDate.Day = MyDate.Day + 20 // Triggers a WLanguage error because the day is equal to 45

// Correct code
MyDate is Date = "20201126" // 11/26/2020
MyDate.Day += 20

// Code triggering the error
MyDate is Date = "20201126" // 11/26/2020
MyDate1 is Date
MyDate1.Day = MyDate.Day + 20 // Triggers a WLanguage error because the day is equal to 45

// Correct code
MyDate1 = MyDate // 11/26/2004
MyDate1.Day += 20

Case 2: Operations on the days
When performing operations on the dates, the change of month is automatically managed. Therefore, if the number of days is greater than the number of days in the month, the number of days restarts from 1 and the number of the month is automatically modified. The year is also modified if necessary (month of December for instance).
For example:

StartDate is Date = "20201226" // 12/26/2020
// Add 10 days to the date
StartDate.Day +=10 // StartDate is "20050105"

Handling the durations

A duration has no limit: the number of days can exceed 30 or 31 days.

Operators available for the days

The following arithmetic operators can be used with the Day property:

++ and --
+= and - =

StartDate is Date = "20201126"
StartDate.Day++ // Add 1 day to the date
StartDate.Day+=5 // Add 5 days ot the date
StartDate.Day-=5 // Subtract 5 days to the date

Calculating the last day of the month

To get the last day of a month, simply assign 31 to the Day property of the date. The last day will be automatically calculated according to the specified month.

StartDate is Date = "20201126"
StartDate.Day = 31
// November does not have 31 days
// The day is automatically replaced with 30

Calculating a 90-day end-of-month due date

The Day property can be used to calculate a 90-day end-of-month due date.

MyDate is Date = "20201126"
MyDate.Day += 90
MyDate.Day = 31

Calculating the end of a 30-day period

A 30-day period corresponds to a one-month period from a given date. The Month and Day properties can be used to easily calculate the end date of a 30-day period.

StartDate is Date = "20201126"
EndDate is Date = StartDate
EndDate.Month++
EndDate.Day--

Calculations on dates

The date storage format allows you to store dates from 01/01/0001 to 12/31/9999.

WLanguage functions and WLanguage properties make accurate calculations on dates from January 1st, 1583.