VB6Parse / Library / Datetime / weekdayname

VB6 WeekdayName Function The WeekdayName function returns a string indicating the specified day of the week.

Syntax

WeekdayName(weekday[, abbreviate[, firstdayofweek]])

Parameters

• weekday: Required. The numeric designation for the day of the week. Numeric value of each day depends on the firstdayofweek setting.
• abbreviate: Optional. Boolean value that indicates if the weekday name is to be abbreviated. If omitted, the default is False (not abbreviated).
• firstdayofweek: Optional. Numeric value indicating the first day of the week. See Settings section for values.

FirstDayOfWeek Constants

• vbUseSystemDayOfWeek (0): Use National Language Support (NLS) API setting
• vbSunday (1): Sunday (default)
• vbMonday (2): Monday
• vbTuesday (3): Tuesday
• vbWednesday (4): Wednesday
• vbThursday (5): Thursday
• vbFriday (6): Friday
• vbSaturday (7): Saturday

Returns

Returns a String containing the name of the specified day of the week. The string is localized based on the system's regional settings.

Remarks

The WeekdayName function provides localized day names: - Localization: Returns day names according to system locale (e.g., "Monday" in English, "Lundi" in French) - Abbreviation: When abbreviate is True, returns shortened form (e.g., "Mon" instead of "Monday") - Weekday parameter: Numeric value from 1 to 7 - Default first day: Sunday (vbSunday = 1) if firstdayofweek not specified - Consistency with Weekday: Use same firstdayofweek value as Weekday function for consistency - System locale: Output language depends on Windows regional settings - Case sensitivity: Returned string typically has proper capitalization - Abbreviation length: Typically 3 characters in English, varies by locale

Understanding Weekday Parameter

The weekday parameter's meaning depends on firstdayofweek: - If firstdayofweek is vbSunday (default): 1=Sunday, 2=Monday, 3=Tuesday, etc. - If firstdayofweek is vbMonday: 1=Monday, 2=Tuesday, 3=Wednesday, etc. - The number always refers to the position in the week, starting from the specified first day

Abbreviation Examples (English locale)

• Full: "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
• Abbreviated: "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"

Combining with Weekday Function

' Get the name of today's day
dayName = WeekdayName(Weekday(Date))

Typical Uses

1. Display Day Names: Show user-friendly day names in UI
2. Report Headers: Label columns or sections with day names
3. Calendar Applications: Display calendar grid headers
4. Localized Applications: Provide day names in user's language
5. Schedule Display: Show schedule with day names
6. Date Formatting: Create custom date format strings
7. Dropdown Lists: Populate day selection dropdowns
8. Log Files: Human-readable date information in logs

Basic Examples

Example 1: Get Today's Day Name

Sub ShowTodayName()
    Dim todayName As String
    todayName = WeekdayName(Weekday(Date))
    MsgBox "Today is " & todayName
End Sub

Example 2: Display All Day Names

Sub ListAllDays()
    Dim i As Integer
    For i = 1 To 7
        Debug.Print WeekdayName(i)
    Next i
End Sub

Example 3: Abbreviated Day Names

Function GetAbbreviatedDayName(dayNumber As Integer) As String
    GetAbbreviatedDayName = WeekdayName(dayNumber, True)
End Function
' Usage:
Debug.Print GetAbbreviatedDayName(1) ' Prints "Sun" (if vbSunday is first day)

Example 4: Create Calendar Header

Function CreateCalendarHeader(Optional abbreviated As Boolean = True) As String
    Dim i As Integer
    Dim header As String
    header = ""
    For i = 1 To 7
        header = header & WeekdayName(i, abbreviated, vbSunday) & vbTab
    Next i
    CreateCalendarHeader = header
End Function

Common Patterns

Pattern 1: Format Date with Day Name

Function FormatDateWithDayName(dt As Date) As String
    FormatDateWithDayName = WeekdayName(Weekday(dt)) & ", " & Format$(dt, "mmmm d, yyyy")
End Function

Pattern 2: Get All Day Names Array

Function GetDayNamesArray(Optional abbreviated As Boolean = False) As String()
    Dim days(1 To 7) As String
    Dim i As Integer
    For i = 1 To 7
        days(i) = WeekdayName(i, abbreviated)
    Next i
    GetDayNamesArray = days
End Function

Pattern 3: ISO Week Day Names (Monday First)

Function GetISODayName(dayNumber As Integer, Optional abbreviated As Boolean = False) As String
    GetISODayName = WeekdayName(dayNumber, abbreviated, vbMonday)
End Function

Pattern 4: Populate ComboBox with Days

Sub PopulateDayCombo(combo As ComboBox)
    Dim i As Integer
    combo.Clear
    For i = 1 To 7
        combo.AddItem WeekdayName(i)
    Next i
End Sub

Pattern 5: Get Day Initials

Function GetDayInitial(dayNumber As Integer) As String
    GetDayInitial = Left$(WeekdayName(dayNumber, True), 1)
End Function

Pattern 6: Create Week Schedule Header

Function CreateWeekSchedule() As String
    Dim i As Integer
    Dim schedule As String
    schedule = "Week Schedule:" & vbCrLf
    For i = 1 To 7
        schedule = schedule & WeekdayName(i) & ": _____" & vbCrLf
    Next i
    CreateWeekSchedule = schedule
End Function

Pattern 7: Format Event Description

Function FormatEventDescription(eventDate As Date, eventName As String) As String
    FormatEventDescription = eventName & " on " & _
                            WeekdayName(Weekday(eventDate)) & ", " & _
                            Format$(eventDate, "mmmm d")
End Function

Pattern 8: Get Weekday vs Weekend Label

Function GetDayTypeLabel(dt As Date) As String
    Dim dayNum As Integer
    dayNum = Weekday(dt)
    If dayNum = vbSaturday Or dayNum = vbSunday Then
        GetDayTypeLabel = WeekdayName(dayNum) & " (Weekend)"
    Else
        GetDayTypeLabel = WeekdayName(dayNum) & " (Weekday)"
    End If
End Function

Pattern 9: Create Pivot Headers

Function CreatePivotDayHeaders() As Variant
    Dim headers(1 To 7) As String
    Dim i As Integer
    For i = 1 To 7
        headers(i) = WeekdayName(i, True, vbMonday)
    Next i
    CreatePivotDayHeaders = headers
End Function

Pattern 10: Conditional Day Name Display

Function GetDisplayDayName(dt As Date, useAbbreviation As Boolean) As String
    GetDisplayDayName = WeekdayName(Weekday(dt), useAbbreviation)
End Function

Advanced Usage

Example 1: Calendar Header Generator Class

' Class: CalendarHeaderGenerator
' Generates calendar headers with configurable options
Option Explicit
Private m_FirstDayOfWeek As VbDayOfWeek
Private m_Abbreviated As Boolean
Private m_Separator As String
Public Sub Initialize(Optional firstDay As VbDayOfWeek = vbSunday, _
                     Optional abbreviated As Boolean = True, _
                     Optional separator As String = " ")
    m_FirstDayOfWeek = firstDay
    m_Abbreviated = abbreviated
    m_Separator = separator
End Sub
Public Function GenerateHeader() As String
    Dim i As Integer
    Dim header As String
    header = ""
    For i = 1 To 7
        If i > 1 Then header = header & m_Separator
        header = header & WeekdayName(i, m_Abbreviated, m_FirstDayOfWeek)
    Next i
    GenerateHeader = header
End Function
Public Function GenerateHeaderArray() As String()
    Dim headers(1 To 7) As String
    Dim i As Integer
    For i = 1 To 7
        headers(i) = WeekdayName(i, m_Abbreviated, m_FirstDayOfWeek)
    Next i
    GenerateHeaderArray = headers
End Function
Public Function GetDayName(dayNumber As Integer) As String
    If dayNumber < 1 Or dayNumber > 7 Then
        Err.Raise 5, , "Day number must be between 1 and 7"
    End If
    GetDayName = WeekdayName(dayNumber, m_Abbreviated, m_FirstDayOfWeek)
End Function

Example 2: Date Formatter Module

' Module: DateFormatter
' Advanced date formatting with day names
Option Explicit
Public Function FormatLongDate(dt As Date) As String
    FormatLongDate = WeekdayName(Weekday(dt)) & ", " & _
                    Format$(dt, "mmmm d, yyyy")
End Function
Public Function FormatShortDate(dt As Date) As String
    FormatShortDate = WeekdayName(Weekday(dt), True) & " " & _
                     Format$(dt, "mm/dd/yyyy")
End Function
Public Function FormatScheduleDate(dt As Date) As String
    FormatScheduleDate = WeekdayName(Weekday(dt), True) & ", " & _
                        Format$(dt, "mmm d")
End Function
Public Function FormatCalendarDate(dt As Date) As String
    FormatCalendarDate = WeekdayName(Weekday(dt)) & vbCrLf & _
                        Format$(dt, "d")
End Function
Public Function GetDayWithOrdinal(dt As Date) As String
    Dim dayNum As Integer
    Dim suffix As String
    dayNum = Day(dt)
    Select Case dayNum
        Case 1, 21, 31
            suffix = "st"
        Case 2, 22
            suffix = "nd"
        Case 3, 23
            suffix = "rd"
        Case Else
            suffix = "th"
    End Select
    GetDayWithOrdinal = WeekdayName(Weekday(dt)) & ", " & _
                       MonthName(Month(dt)) & " " & dayNum & suffix
End Function

Example 3: Schedule Analyzer Class

' Class: ScheduleAnalyzer
' Analyzes schedules and provides day-based insights
Option Explicit
Public Function GetDayDistributionReport(dates() As Date) As String
    Dim dayCounts(1 To 7) As Integer
    Dim i As Long
    Dim report As String
    Dim dayNum As Integer
    ' Count occurrences
    For i = LBound(dates) To UBound(dates)
        dayNum = Weekday(dates(i))
        dayCounts(dayNum) = dayCounts(dayNum) + 1
    Next i
    ' Build report
    report = "Day Distribution:" & vbCrLf
    For i = 1 To 7
        report = report & WeekdayName(i) & ": " & dayCounts(i) & vbCrLf
    Next i
    GetDayDistributionReport = report
End Function
Public Function GetMostCommonDay(dates() As Date) As String
    Dim dayCounts(1 To 7) As Integer
    Dim i As Long
    Dim maxCount As Integer
    Dim maxDay As Integer
    Dim dayNum As Integer
    For i = LBound(dates) To UBound(dates)
        dayNum = Weekday(dates(i))
        dayCounts(dayNum) = dayCounts(dayNum) + 1
    Next i
    maxCount = 0
    maxDay = 1
    For i = 1 To 7
        If dayCounts(i) > maxCount Then
            maxCount = dayCounts(i)
            maxDay = i
        End If
    Next i
    GetMostCommonDay = WeekdayName(maxDay)
End Function
Public Function CreateDaySummary(dates() As Date) As Collection
    Dim summary As New Collection
    Dim i As Integer
    For i = 1 To 7
        summary.Add 0, WeekdayName(i)
    Next i
    Dim dt As Variant
    For Each dt In dates
        Dim dayName As String
        dayName = WeekdayName(Weekday(dt))
        summary.Remove dayName
        summary.Add summary(dayName) + 1, dayName
    Next dt
    Set CreateDaySummary = summary
End Function

Example 4: Localization Helper Module

' Module: LocalizationHelper
' Helps with localized day name handling
Option Explicit
Public Function GetLocalizedDayNames(Optional abbreviated As Boolean = False, _
                                    Optional firstDay As VbDayOfWeek = vbSunday) As String()
    Dim names(1 To 7) As String
    Dim i As Integer
    For i = 1 To 7
        names(i) = WeekdayName(i, abbreviated, firstDay)
    Next i
    GetLocalizedDayNames = names
End Function
Public Function CreateDayNameLookup(Optional abbreviated As Boolean = False) As Collection
    Dim lookup As New Collection
    Dim i As Integer
    For i = 1 To 7
        lookup.Add WeekdayName(i, abbreviated), CStr(i)
    Next i
    Set CreateDayNameLookup = lookup
End Function
Public Function FindDayNumber(dayName As String) As Integer
    Dim i As Integer
    For i = 1 To 7
        If UCase$(WeekdayName(i)) = UCase$(dayName) Then
            FindDayNumber = i
            Exit Function
        End If
        If UCase$(WeekdayName(i, True)) = UCase$(dayName) Then
            FindDayNumber = i
            Exit Function
        End If
    Next i
    FindDayNumber = 0 ' Not found
End Function
Public Function IsDayNameValid(dayName As String) As Boolean
    IsDayNameValid = (FindDayNumber(dayName) > 0)
End Function
Public Function NormalizeDayName(dayName As String) As String
    Dim dayNum As Integer
    dayNum = FindDayNumber(dayName)
    If dayNum > 0 Then
        NormalizeDayName = WeekdayName(dayNum)
    Else
        NormalizeDayName = ""
    End If
End Function

Error Handling

The WeekdayName function can raise the following errors: - Error 5 (Invalid procedure call or argument): If weekday is less than 1 or greater than 7 - Error 5 (Invalid procedure call or argument): If firstdayofweek is not between 0 and 7 - Error 13 (Type mismatch): If arguments are not of correct type

Performance Notes

• Very fast operation - simple lookup/formatting
• Constant time O(1) complexity
• No significant performance difference between abbreviated and full forms
• Can be called repeatedly without performance concerns
• Consider caching day name arrays if used frequently in loops

Best Practices

1. Use consistent firstdayofweek with Weekday function to avoid confusion
2. Cache day name arrays if populating lists or grids repeatedly
3. Handle localization - day names will differ based on system locale
4. Document expectations about which day is first in week
5. Use abbreviation parameter for space-constrained displays
6. Validate weekday range (1-7) before calling
7. Consider MonthName for consistent date formatting patterns
8. Test with different locales if application is internationalized
9. Use named constants (vbMonday, etc.) for clarity
10. Combine with Format$ for custom date displays

Comparison Table

Platform Notes

• Available in VB6, VBA, and VBScript
• Behavior consistent across platforms
• Output localized based on system regional settings
• Abbreviation format varies by locale
• English (US): "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
• Other languages will return appropriate translations

Limitations

• Cannot customize day name output (uses system locale)
• Abbreviation length not configurable (determined by locale)
• No way to get day name in specific language (uses system setting)
• Cannot get day names for custom calendars (e.g., Hebrew, Islamic)
• No built-in way to get single-letter day abbreviations
• Cannot specify case (capitalization) of returned string