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Distinct Values Function

This page describes a VBA Function that will return an array of the distinct values in a range or array of
input values.

Introduction

Excel has some manual methods, such as Advanced Filter, for getting a list of distinct items from an input range. The drawback of using such methods is that you must manually refresh the results when the input data changes. Moreover, these methods work only with ranges, not arrays of values, and, not being functions, cannot be called from worksheet cells or incorporated into array formulas. This page describes a VBA function called DistinctValues that accepts as input either a range or an array of data and returns as its result an array containing the distinct items from the input list. That is, the elements with all duplicates removed. The order of the input elements is preserved. The order of the elements in the output array is the same as the order in the input values. The function can be called from an array entered range on a worksheet (see this page for information about array formulas), or from in an array formula in a single worksheet cell, or from another VB function.

The function declaration is shown below:

Function DistinctValues(InputValues As Variant, _ Optional IgnoreCase As Boolean = False) As Variant

You can download an example workbook or just the bas module file with the complete code.

The parameter InputValues is either a range on a worksheet or an array of values. If it is a worksheet range, the range must have exactly one column or one row. Two-dimensional ranges are not supported. If InputValues is an array, it must be a single dimensional array. Two-dimensional arrays are not supported. The parameter IgnoreCase indicates whether the comparisons should be case-sensitive or case-insensitive. If this value is True, case is ignored and

If the function is array entered into a range on a worksheet, the size of the returned array is equal to the size of the range into which the function was entered, regardless of the number of distinct elements found, and unused entries at the end of the resulting array are set to vbNullStrings. This prevents #N/A errors from appearing. Note that this differs from the default behavior of Excel's own array formulas. If the function is entered in a single cell array formula, the size of the result array is equal to the number of distinct elements from the input list. Similarly, if the function is called from another VB function, not from a worksheet cell, the result array contains only the distinct elements.

Empty elements, those with a value of vbNullString or Empty are not counted as distinct elements -- they are ignored. Thus, the array {"a","b","","","c"} has three distinct elements, a, b, and c. The empty string is ignored by the function. Spaces and zero values, however, are considered when creating the list of distinct elements.

If an array, not a range, is passed into DistinctValues, that array must not contain any Object type variables (other than Excel.Range objects) and must not contain any Null values.

Examples Of Calling DistinctValues

The most common usage is to array enter the DistinctValues function into a range of cells and pass it
another range of cells as the input list. For example, select cells B1:B10 type

=DistinctValues(A1:A10,FALSE)

and press CTRL SHIFT ENTER. This list of distinct values from cells A1:A10 will
be returned to cells B1:B10. Unpopulated cells in B1:B10 will be filled
with empty strings.

You can also use DistinctValues in an array formula. For example,

=MATCH("chip",DistinctValues(A1:A10,TRUE),0)

will return the position of the string *chip* in the list of distinct values from cells A1:A10.

To count the number of distinct values in a range, just pass the results of DistinctValue to the
COUNT or COUNTA function:

=COUNTA(DistinctValues(A1:A10,TRUE))

In addition, the DistinctValues function may be called from other VB code, passing either a Range or an
Array as the input parameter. For example,

Sub Test() Dim InputRange As Range Dim ResultArray As Variant Dim Ndx As Long Set InputRange = Range("InputValues") ResultArray = DistinctValues(InputValues:=InputRange, IgnoreCase:=True) If IsArray(ResultArray) = True Then For Ndx = LBound(ResultArray) To UBound(ResultArray) Debug.Print ResultArray(Ndx) Next Ndx Else If IsError(ResultArray) = True Then Debug.Print "ERROR: " & CStr(ResultArray) Else Debug.Print "UNEXPECTED RESULT: " & CStr(ResultArray) End If End If End Sub

In addition to a range, the InputValues can be an array literal. For example,

=DistinctValues({"a","b","a","b","c"},TRUE)

The Code For Distinct Values

The code for the DistinctValues function is shown below. It requires the
NumberOfArrayDimensions, TransposeArray, and
Transpose1DArray functions, all of which are listed below following the listing for
DisinctValues.

You can download an example workbook or just the bas
module file with the complete code.

Option Explicit ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' modDistinctValues ' By Chip Pearson, 5-November-2007, chip@cpearson.com, www.cpearson.com ' This page: www.cpearson.com/Excel/DistinctValues.apsx ' ' This module contains the DistinctValues function and supporting procedures. You ' should import the entire module into your project. The DistinctValues function ' takes in a Range or an Array as input and returns an Array containing the disinct ' values from that array of inputs. ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' Function DistinctValues(InputValues As Variant, _ Optional IgnoreCase As Boolean = False) As Variant ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' DistinctValues ' This function accepts a set of values in InputValues and returns an Array ' containing the distinct items in that input set. The order of elements in the result ' array is the same as in the InputValues. InputValues may be either a Range object ' or an Array. In either case, it must be one-dimensional (in the case of a Range, ' it may be either a row or column range). If InputValues has more than one dimension, ' the function returns a #REF error. The IgnoreCase parameter indicates whether to do ' a case-sensitive or case-insensitive comparison when comparing text values. If TRUE, ' case is ignored and 'abc' is treated the same as 'ABC'. If FALSE, case is taken into ' account and 'abc' is treated differently than 'ABC'. ' ' If the function is called from a worksheet, it must be array entered (CTRL SHIFT ENTER) ' into the array of cells that will receive the resutling Distinct values. The size of ' the returned array will be the same size as the array into which the function was ' entered. The Distinct values will fill the first N cells and the remaining array entries ' will be vbNullStrings. The result is properly transposed (or not) depending on whether ' it was called from a row-range or a column-range of cells on the worksheet. ' The result array is always sized to match the size of the range into which it was ' entered, even if that array contains more entries than the InputValues range. This behavior ' differs from the standard behavior of Excel's own array functions. ' ' If the function is called by another VBA procedure, not from worksheet cells, the ' array is a single dimensional array with only enough elements to contain the Distinct ' elements. The LBound of the array is 1. The variable that receives the array of distinct ' values should be declared as a Variant: ' Dim Res As Variant ' Res = DistinctElements(MyArray,True) ' ' Empty elements, those with a value of vbNullString or Empty, are not compared. Thus, ' vbNullString and Empty are not considered values in the own right and are not counted ' amongst the Distinct Values. NULL values are not allowed in the InputValues and the ' presence of a NULL value will cause an #NULL error, If there is an Object type variable ' in the InputValues other than a Range object, a #VALUE error will be returned. ' ' String representations of numbers are considered the same as numbers, so 2 and "2" ' are not distict values. ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' Dim ResultArray() As Variant Dim UB As Long Dim TransposeAtEnd As Boolean Dim N As Long Dim ResultIndex As Long Dim M As Long Dim ElementFoundInResults As Boolean Dim NumCells As Long Dim ReturnSize As Long Dim Comp As VbCompareMethod Dim V As Variant '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Set the text comparison value to be used by StrComp based on ' the setting of IgnoreCase. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' If IgnoreCase = True Then Comp = vbTextCompare Else Comp = vbBinaryCompare End If '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' This first large block of code determines whether the function ' is being called from a worksheet range or by another function. ' If it is being called from a worksheet, it must be called from ' a range with only one column or only one row. Two-dimensional ' ranges will cause a #REF error. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' If IsObject(Application.Caller) = True Then If Application.Caller.Rows.Count > 1 And Application.Caller.Columns.Count > 1 Then DistinctValues = CVErr(xlErrRef) Exit Function End If '''''''''''''''''''''''''''''''''''''''''''''''''' ' Save the size of the region from which the ' function was called and save a flag indicating ' whether we need to transpose the result upon ' returning. '''''''''''''''''''''''''''''''''''''''''''''''''' If Application.Caller.Rows.Count > 1 Then TransposeAtEnd = True ReturnSize = Application.Caller.Rows.Count Else TransposeAtEnd = False ReturnSize = Application.Caller.Columns.Count End If End If '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Were we passed a Range object or a VBA array? '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' If IsObject(InputValues) = True Then If TypeOf InputValues Is Excel.Range Then '''''''''''''''''''''''''''''''''''''''''''''''' ' Input is a Range object. '''''''''''''''''''''''''''''''''''''''''''''''' If InputValues.Rows.Count > 1 And InputValues.Columns.Count > 1 Then DistinctValues = CVErr(xlErrRef) Exit Function End If If InputValues.Rows.Count > 1 Then NumCells = InputValues.Rows.Count Else NumCells = InputValues.Columns.Count End If UB = NumCells Else DistinctValues = CVErr(xlErrRef) Exit Function End If Else ''''''''''''''''''''''''''''''''''''''''''''''''''''' ' InputValues is not a Range object. ''''''''''''''''''''''''''''''''''''''''''''''''''''' If IsArray(InputValues) = True Then Select Case NumberOfArrayDimensions(InputValues) Case 0 '''''''''''''''''''''''''''''''''''' ' Zero dimensional array (scalar). ' Return an array of 1 element with ' that value. '''''''''''''''''''''''''''''''''''' ReDim ResultArray(1 To 1) ResultArray(1) = InputValues DistinctValues = ResultArray Exit Function Case 1 UB = UBound(InputValues) - LBound(InputValues) + 1 ''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' If we were passed in an array from a worksheet ' function (e.g., =DISTINCTVALUES({1,2,3}), we ' need to set NumCells to the size of the input array. ' This is used later to properly resize the result array. ''''''''''''''''''''''''''''''''''''''''''''''''''''''' If IsObject(InputValues) = False Then NumCells = UB End If Case Else DistinctValues = CVErr(xlErrValue) Exit Function End Select Else ReDim ResultArray(1 To 1) ResultArray(1) = InputValues DistinctValues = ResultArray Exit Function End If End If '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Ensure we don't have any NULLs or Objects in the InputValues. ' A Range object is allowed. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' For Each V In InputValues If IsNull(V) = True Then DistinctValues = CVErr(xlErrNull) Exit Function End If If IsObject(V) = True Then If Not TypeOf V Is Excel.Range Then DistinctValues = CVErr(xlErrValue) Exit Function End If End If Next V '''''''''''''''''''''''''''''''''''''''''''''''''' ' Allocate the ResultArray and fill it with either ' vbNullStrings if we were called from a worksheet ' or with Empty values if called by a VB procedure. ''''''''''''''''''''''''''''''''''''''''''''''''''' ReDim ResultArray(1 To UB) For N = LBound(ResultArray) To UBound(ResultArray) If IsObject(Application.Caller) = True Then ResultArray(N) = vbNullString Else ResultArray(N) = Empty End If Next N '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' This is the logic that actually tests for duplicate values. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ResultIndex = 1 '''''''''''''''''''''''''''''''''''' ' We can always assume that the ' first element in the InputValues ' will be distinct so far. '''''''''''''''''''''''''''''''''''' ResultArray(1) = InputValues(1) '''''''''''''''''''''''''''''''''''''''' ' Loop throught the entire InputValues ' array. '''''''''''''''''''''''''''''''''''''''' For N = 2 To UB ''''''''''''''''''''''''''''''''' ' Set our Found flag = False. This ' flag is used to indicate whether ' we find Input(N) in the list of ' distinct elements. If we found it ' earlier, it is no longer a distinct ' element and we won't put it in the ' ResultArray. '''''''''''''''''''''''''''''''''''' ElementFoundInResults = False For M = 1 To N ''''''''''''''''''''''''''''''''''''' ' Scan through the array ResultArray ' looking for Input(N). If we find it, ' Input(N) is a duplicate so set the ' Found flag to True. ''''''''''''''''''''''''''''''''''''' If StrComp(CStr(ResultArray(M)), CStr(InputValues(N)), Comp) = 0 Then ElementFoundInResults = True Exit For End If Next M '''''''''''''''''''''''''''''''''''''''''''' ' If we didn't find Input(N) in ResultArray ' then Input(N) is distinct so we increment ' ResultIndexand add Input(N) to ResultArray. '''''''''''''''''''''''''''''''''''''''''''' If ElementFoundInResults = False Then ResultIndex = ResultIndex + 1 ResultArray(ResultIndex) = InputValues(N) End If Next N '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Here, we resize the ResultArray to the appropriate number of ' elements. ResultIndex is equal to the number of distinct elements found. ' If the function was called from a worksheet, ReturnSize is ' positive, equal to the number of cells in the array into which ' the function was entered and NumCells is the number of cells in ' the InputRange. If the function was called by another VB function, ' not from a worksheet, ReturnSizse and NumCells will be 0. Thus, ' if ReturnSize is not 0 and ResultIndex, the number of distinct elements, ' is less than the number of cells from in the InputValues, we ' set ResultIndex to the number of cells from which the function was called. ' This allows us in the For N loop that follows to pad out the ' entire Application.Caller range with vbNullStrings to prevent ' #N/A errors if the function is called from a range with more cells ' than there were disticnt elements. Note that this behavior differs ' from Excel's normal array formula handling. ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' If ReturnSize <> 0 Then If ResultIndex < NumCells Then If ResultIndex < ReturnSize Then ResultIndex = ReturnSize End If End If End If ReDim Preserve ResultArray(1 To ResultIndex) If UBound(ResultArray) > NumCells Then For N = NumCells + 1 To ReturnSize ResultArray(N) = vbNullString Next N End If ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' If we were called from a Column range on a worksheet (Rows.Count > 1), ' we need to transform ResultArray into a 2-dimensional array and transpose ' it so it will be properly stored in the column. Transpose1DArray does this ' function. If the function was not called from a worksheet, then the ' TransposeAtEnd flag will be false and we just return the array. ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' If TransposeAtEnd = True Then DistinctValues = Transpose1DArray(Arr:=ResultArray, ToRow:=False) Else DistinctValues = ResultArray End If End Function Function TransposeArray(Arr As Variant) As Variant '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' TransposeArray ' This function tranposes the array Arr. Arr must be ' a two dimensional array. If Arr is not an array, the ' result is just Arr itself. If Arr is a 1-dimensional ' array, the result is just Arr itself. If you need to ' transpose a 1-dimensional array from a row to a column ' in order to properly return it to a worksheet, use ' Transpose1DArray. If Arr has more than three dimensions, ' an error value is returned. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' Dim R1 As Long Dim R2 As Long Dim C1 As Long Dim C2 As Long Dim LB1 As Long Dim LB2 As Long Dim UB1 As Long Dim UB2 As Long Dim Res() As Variant Dim NumDims As Long If IsArray(Arr) = False Then TransposeArray = Arr Exit Function End If NumDims = NumberOfArrayDimensions(Arr) Select Case NumDims Case 0 If IsObject(Arr) = True Then Set TransposeArray = Arr Else TransposeArray = Arr End If Case 1 TransposeArray = Arr Case 2 LB1 = LBound(Arr, 1) UB1 = UBound(Arr, 1) LB2 = LBound(Arr, 2) UB2 = UBound(Arr, 2) R2 = LB1 C2 = LB2 ReDim Res(LB2 To UB2, LB1 To UB1) For R1 = LB1 To UB1 For C1 = LB2 To UB2 Res(C1, R1) = Arr(R1, C1) C2 = C2 + 1 Next C1 R2 = R2 + 1 Next R1 TransposeArray = Res Case Else TransposeArray = CVErr(9) End Select End Function Function NumberOfArrayDimensions(Arr As Variant) As Long '''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' NumberOfArrayDimensions ' This returns the number of dimensions of the array ' Arr. If Arr is not an array, the result is 0. '''''''''''''''''''''''''''''''''''''''''''''''''''''''' Dim LB As Long Dim N As Long On Error Resume Next N = 1 Do Until Err.Number <> 0 LB = LBound(Arr, N) N = N + 1 Loop NumberOfArrayDimensions = N - 2 End Function Function Transpose1DArray(Arr As Variant, ToRow As Boolean) As Variant '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Transpose1DArray ' This function transforms a 1-dim array to a 2-dim array and ' transposes it. This is required when returning arrays back to ' worksheet cells. The ToRow parameter determines if the array is ' to be returned to the worksheet as a row (TRUE) or as a columns (FALSE). ' This should only be used for 1-dim arrays that are going back to ' a worksheet. ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' Dim Res As Variant Dim N As Long If IsArray(Arr) = False Then Transpose1DArray = CVErr(xlErrValue) Exit Function End If If NumberOfArrayDimensions(Arr) <> 1 Then Transpose1DArray = CVErr(xlErrValue) Exit Function End If If ToRow = True Then ReDim Res(LBound(Arr) To LBound(Arr), LBound(Arr) To UBound(Arr)) For N = LBound(Res, 2) To UBound(Res, 2) Res(LBound(Res), N) = Arr(N) Next N Else ReDim Res(LBound(Arr) To UBound(Arr), LBound(Arr) To LBound(Arr)) For N = LBound(Res, 1) To UBound(Res, 1) Res(N, LBound(Res)) = Arr(N) Next N End If Transpose1DArray = Res End Function

This page last updated: 5-November-2007

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