Difference between revisions of "Documentation/BASIC Guide/Date and Time (Runtime Library)"

Latest revision as of 12:10, 30 January 2021

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Apache OpenOffice Basic provides the Date data type, which saves the date and time details in binary format.

Specification of Date and Time Details within the Program Code

You can assign a date to a date variable through the assignment of a simple string:

Dim MyDate As Date
MyDate = "24.1.2002"

This assignment can function properly because Apache OpenOffice Basic automatically converts the date value defined as a string into a date variable. This type of assignment, however, can cause errors, date and time values are defined and displayed differently in different countries.

Since Apache OpenOffice Basic uses the country-specific settings of the operating system when converting a string into a date value, the expression shown previously only functions correctly if the country-specific settings match the string expression.

To avoid this problem, the DateSerial function should be used to assign a fixed value to a date variable:

Dim MyVar As Date
MyDate = DateSerial (2001, 1, 24)

The function parameter must be in the sequence: year, month, day. The function ensures that the variable is actually assigned the correct value regardless of the country-specific settings

The TimeSerial function formats time details in the same way that the DateSerial function formats dates:

Dim MyVar As Date
MyDate =  TimeSerial(11, 23, 45)

Their parameters should be specified in the sequence: hours, minutes, seconds.

Extracting Date and Time Details

The following functions form the counterpart to the DateSerial and TimeSerial functions:

Day(MyDate)

returns the day of the month from MyDate.

Month(MyDate)

returns the month from MyDate.

Year(MyDate)

returns the year from MyDate.

Weekday(MyDate)

returns the number of the weekday from MyDate.

Hour(MyTime)

returns the hours from MyTime.

Minute(MyTime)

returns the minutes from MyTime.

Second(MyTime)

returns the seconds from MyTime.

These functions extract the date or time sections from a specified Date variable. The following example checks whether the date saved in MyDate is in the year 2023.

Dim MyDate As Date
' ... Initialization of MyDate
 
If Year(MyDate) = 2023 Then
  ' ... Specified date is in the year 2023
End If

In the same way, the following example checks whether MyTime is between 12 and 14 hours.

Dim MyTime As Date
' ... Initialization of MyTime
 
If Hour(MyTime) >= 12 And Hour(MyTime) < 14 Then
  ' ... Specified time is between 12 and 14 hours
End If

The Weekday function returns the number of the weekday for the transferred date:

Dim MyDate As Date
Dim MyWeekday As String
' ... initialize MyDate
 
Select Case WeekDay(MyDate)
  case 1
    MyWeekday = "Sunday"
  case 2
    MyWeekday = "Monday"
  case 3
    MyWeekday = "Tuesday"
  case 4
    MyWeekday = "Wednesday"
  case 5
    MyWeekday = "Thursday"
  case 6
    MyWeekday = "Friday"
  case 7
    MyWeekday = "Saturday"
End Select

Sunday is considered the first day of the week.

Retrieving System Date and Time

The following functions are available in Apache OpenOffice Basic to retrieve the system time and system date:

Date

returns the present date as a string. The format depends on localization settings.

Time

returns the present time as a string.

Now

returns the present point in time (date and time) as a combined value of type Date.