How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops

Question

How can I use regular expressions in Excel and take advantage of Excel's powerful grid-like setup for data manipulation?

• In-cell function to return a matched pattern or replaced value in a string.
• Sub to loop through a column of data and extract matches to adjacent cells.
• What setup is necessary?
• What are Excel's special characters for Regular expressions?

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I understand Regex is not ideal for many situations (To use or not to use regular expressions?) since excel can use Left, Mid, Right, Instr type commands for similar manipulations.

Answer 1

Regular expressions are used for Pattern Matching.

To use in Excel follow these steps:

Step 1: Add VBA reference to "Microsoft VBScript Regular Expressions 5.5"

• Select "Developer" tab (I don't have this tab what do I do?)
• Select "Visual Basic" icon from 'Code' ribbon section
• In "Microsoft Visual Basic for Applications" window select "Tools" from the top menu.
• Select "References"
• Check the box next to "Microsoft VBScript Regular Expressions 5.5" to include in your workbook.
• Click "OK"

Step 2: Define your pattern

Basic definitions:

- Range.

• E.g. a-z matches an lower case letters from a to z
• E.g. 0-5 matches any number from 0 to 5

[] Match exactly one of the objects inside these brackets.

• E.g. [a] matches the letter a
• E.g. [abc] matches a single letter which can be a, b or c
• E.g. [a-z] matches any single lower case letter of the alphabet.

() Groups different matches for return purposes. See examples below.

{} Multiplier for repeated copies of pattern defined before it.

• E.g. [a]{2} matches two consecutive lower case letter a: aa
• E.g. [a]{1,3} matches at least one and up to three lower case letter a, aa, aaa

+ Match at least one, or more, of the pattern defined before it.

• E.g. a+ will match consecutive a's a, aa, aaa, and so on

? Match zero or one of the pattern defined before it.

• E.g. Pattern may or may not be present but can only be matched one time.
• E.g. [a-z]? matches empty string or any single lower case letter.

* Match zero or more of the pattern defined before it.

• E.g. Wildcard for pattern that may or may not be present.
• E.g. [a-z]* matches empty string or string of lower case letters.

. Matches any character except newline \n

• E.g. a. Matches a two character string starting with a and ending with anything except \n

| OR operator

• E.g. a|b means either a or b can be matched.
• E.g. red|white|orange matches exactly one of the colors.

^ NOT operator

• E.g. [^0-9] character can not contain a number
• E.g. [^aA] character can not be lower case a or upper case A

\ Escapes special character that follows (overrides above behavior)

• E.g. \., \\, \(, \?, \$, \^

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Anchoring Patterns:

^ Match must occur at start of string

• E.g. ^a First character must be lower case letter a
• E.g. ^[0-9] First character must be a number.

$ Match must occur at end of string

• E.g. a$ Last character must be lower case letter a

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Precedence table:

Order  Name                Representation 1      Parentheses         ( ) 2      Multipliers         ? + * {m,n} {m, n}? 3      Sequence & Anchors  abc ^ $ 4      Alternation         | 

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Predefined Character Abbreviations:

abr    same as       meaning \d     [0-9]         Any single digit \D     [^0-9]        Any single character that's not a digit \w     [a-zA-Z0-9_]  Any word character \W     [^a-zA-Z0-9_] Any non-word character \s     [ \r\t\n\f]   Any space character \S     [^ \r\t\n\f]  Any non-space character \n     [\n]          New line 

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Example 1: Run as macro

The following example macro looks at the value in cell A1 to see if the first 1 or 2 characters are digits. If so, they are removed and the rest of the string is displayed. If not, then a box appears telling you that no match is found. Cell A1 values of 12abc will return abc, value of 1abc will return abc, value of abc123 will return "Not Matched" because the digits were not at the start of the string.

Private Sub simpleRegex()     Dim strPattern As String: strPattern = "^[0-9]{1,2}"     Dim strReplace As String: strReplace = ""     Dim regEx As New RegExp     Dim strInput As String     Dim Myrange As Range          Set Myrange = ActiveSheet.Range("A1")          If strPattern <> "" Then         strInput = Myrange.Value                  With regEx             .Global = True             .MultiLine = True             .IgnoreCase = False             .Pattern = strPattern         End With                  If regEx.Test(strInput) Then             MsgBox (regEx.Replace(strInput, strReplace))         Else             MsgBox ("Not matched")         End If     End If End Sub 

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Example 2: Run as an in-cell function

This example is the same as example 1 but is setup to run as an in-cell function. To use, change the code to this:

Function simpleCellRegex(Myrange As Range) As String     Dim regEx As New RegExp     Dim strPattern As String     Dim strInput As String     Dim strReplace As String     Dim strOutput As String               strPattern = "^[0-9]{1,3}"          If strPattern <> "" Then         strInput = Myrange.Value         strReplace = ""                  With regEx             .Global = True             .MultiLine = True             .IgnoreCase = False             .Pattern = strPattern         End With                  If regEx.test(strInput) Then             simpleCellRegex = regEx.Replace(strInput, strReplace)         Else             simpleCellRegex = "Not matched"         End If     End If End Function 

Place your strings ("12abc") in cell A1. Enter this formula =simpleCellRegex(A1) in cell B1 and the result will be "abc".

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Example 3: Loop Through Range

This example is the same as example 1 but loops through a range of cells.

Private Sub simpleRegex()     Dim strPattern As String: strPattern = "^[0-9]{1,2}"     Dim strReplace As String: strReplace = ""     Dim regEx As New RegExp     Dim strInput As String     Dim Myrange As Range          Set Myrange = ActiveSheet.Range("A1:A5")          For Each cell In Myrange         If strPattern <> "" Then             strInput = cell.Value                          With regEx                 .Global = True                 .MultiLine = True                 .IgnoreCase = False                 .Pattern = strPattern             End With                          If regEx.Test(strInput) Then                 MsgBox (regEx.Replace(strInput, strReplace))             Else                 MsgBox ("Not matched")             End If         End If     Next End Sub 

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Example 4: Splitting apart different patterns

This example loops through a range (A1, A2 & A3) and looks for a string starting with three digits followed by a single alpha character and then 4 numeric digits. The output splits apart the pattern matches into adjacent cells by using the (). $1 represents the first pattern matched within the first set of ().

Private Sub splitUpRegexPattern()     Dim regEx As New RegExp     Dim strPattern As String     Dim strInput As String     Dim Myrange As Range          Set Myrange = ActiveSheet.Range("A1:A3")          For Each C In Myrange         strPattern = "(^[0-9]{3})([a-zA-Z])([0-9]{4})"                  If strPattern <> "" Then             strInput = C.Value                          With regEx                 .Global = True                 .MultiLine = True                 .IgnoreCase = False                 .Pattern = strPattern             End With                          If regEx.test(strInput) Then                 C.Offset(0, 1) = regEx.Replace(strInput, "$1")                 C.Offset(0, 2) = regEx.Replace(strInput, "$2")                 C.Offset(0, 3) = regEx.Replace(strInput, "$3")             Else                 C.Offset(0, 1) = "(Not matched)"             End If         End If     Next End Sub 

Results:

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Additional Pattern Examples

String   Regex Pattern                  Explanation a1aaa    [a-zA-Z][0-9][a-zA-Z]{3}       Single alpha, single digit, three alpha characters a1aaa    [a-zA-Z]?[0-9][a-zA-Z]{3}      May or may not have preceding alpha character a1aaa    [a-zA-Z][0-9][a-zA-Z]{0,3}     Single alpha, single digit, 0 to 3 alpha characters a1aaa    [a-zA-Z][0-9][a-zA-Z]*         Single alpha, single digit, followed by any number of alpha characters  </i8>    \<\/[a-zA-Z][0-9]\>            Exact non-word character except any single alpha followed by any single digit 

Answer 2

To make use of regular expressions directly in Excel formulas the following UDF (user defined function) can be of help. It more or less directly exposes regular expression functionality as an excel function.

How it works

It takes 2-3 parameters.

1. A text to use the regular expression on.
2. A regular expression.
3. A format string specifying how the result should look. It can contain $0, $1, $2, and so on. $0 is the entire match, $1 and up correspond to the respective match groups in the regular expression. Defaults to $0.

Some examples

Extracting an email address:

=regex("Peter Gordon: [email protected], 47", "\w+@\w+\.\w+") =regex("Peter Gordon: [email protected], 47", "\w+@\w+\.\w+", "$0") 

Results in: [email protected]

Extracting several substrings:

=regex("Peter Gordon: [email protected], 47", "^(.+): (.+), (\d+)$", "E-Mail: $2, Name: $1") 

Results in: E-Mail: [email protected], Name: Peter Gordon

To take apart a combined string in a single cell into its components in multiple cells:

=regex("Peter Gordon: [email protected], 47", "^(.+): (.+), (\d+)$", "$" & 1) =regex("Peter Gordon: [email protected], 47", "^(.+): (.+), (\d+)$", "$" & 2) 

Results in: Peter Gordon [email protected] ...

How to use

To use this UDF do the following (roughly based on this Microsoft page. They have some good additional info there!):

1. In Excel in a Macro enabled file ('.xlsm') push ALT+F11 to open the Microsoft Visual Basic for Applications Editor.
2. Add VBA reference to the Regular Expressions library (shamelessly copied from Portland Runners++ answer):
   1. Click on Tools -> References (please excuse the german screenshot)
   2. Find Microsoft VBScript Regular Expressions 5.5 in the list and tick the checkbox next to it.
   3. Click OK.

3. Click on Insert Module. If you give your module a different name make sure the Module does not have the same name as the UDF below (e.g. naming the Module Regex and the function regex causes #NAME! errors).

   

4. In the big text window in the middle insert the following:

   Function regex(strInput As String, matchPattern As String, Optional ByVal outputPattern As String = "$0") As Variant     Dim inputRegexObj As New VBScript_RegExp_55.RegExp, outputRegexObj As New VBScript_RegExp_55.RegExp, outReplaceRegexObj As New VBScript_RegExp_55.RegExp     Dim inputMatches As Object, replaceMatches As Object, replaceMatch As Object     Dim replaceNumber As Integer      With inputRegexObj         .Global = True         .MultiLine = True         .IgnoreCase = False         .Pattern = matchPattern     End With     With outputRegexObj         .Global = True         .MultiLine = True         .IgnoreCase = False         .Pattern = "\$(\d+)"     End With     With outReplaceRegexObj         .Global = True         .MultiLine = True         .IgnoreCase = False     End With      Set inputMatches = inputRegexObj.Execute(strInput)     If inputMatches.Count = 0 Then         regex = False     Else         Set replaceMatches = outputRegexObj.Execute(outputPattern)         For Each replaceMatch In replaceMatches             replaceNumber = replaceMatch.SubMatches(0)             outReplaceRegexObj.Pattern = "\$" & replaceNumber              If replaceNumber = 0 Then                 outputPattern = outReplaceRegexObj.Replace(outputPattern, inputMatches(0).Value)             Else                 If replaceNumber > inputMatches(0).SubMatches.Count Then                     'regex = "A to high $ tag found. Largest allowed is $" & inputMatches(0).SubMatches.Count & "."                     regex = CVErr(xlErrValue)                     Exit Function                 Else                     outputPattern = outReplaceRegexObj.Replace(outputPattern, inputMatches(0).SubMatches(replaceNumber - 1))                 End If             End If         Next         regex = outputPattern     End If End Function 

5. Save and close the Microsoft Visual Basic for Applications Editor window.