Excel Vba-Similar Function - vba

Question

I'm so confused in resolving this:
In VBA syntax there is this function:
If Left("abcdef",3)="abc" then
Msgbox "True"
This function is too simple but is there any way for e.g.
To have something like this
If left("abcdef",3) is in ["A".."Z"] or if left("1265avd0",2) is in [1..9]
Which mean checking if left ("abcdef",3) which is equal to "abc" is in this Interval ["A".."Z"] or checking if the left("123avd0",2) is numeric and is in the interval of [1..9]
Hope you are understading what I want to do
Can anyone Light me in doing This?

Answer 1

You can use the Like operator for this simple type of comparison.
Option Explicit
Option Compare Text 'for case insensitive matching
Sub dural()
Const S1 As String = "abcdef"
Const S2 As String = "1265avd0"
Debug.Print Left(S1, 3) Like "[A-Z][A-Z][A-Z]"
Debug.Print Left(S2, 2) Like "[1-9][1-9]"
End Sub
Both will return TRUE in this instance.
As pointed out by #chrisneilsen, the comparisons can be simplified to:
S1 Like "[A-Z][A-Z][A-Z]*"
S2 Like "[1-9][1-9]*"
And you can test for either with something like:
If Left(myString, 3) Like "[A-Z][A-Z][A-Z]" or _
Left(myString, 2) Like "[1-9][1-9]" then
'do something
End if
And in the simplified version:
If myString Like "[A-Z][A-Z][A-Z]*" or _
myString Like "[1-9][1-9]*" then
'do something
End if
More complex pattern matching can be done using Regular Expressions.
If you prefer to not set Option Compare then change the alpha patterns to "[A-Za-z]"

Answer 2

You can use Regular Expressions ("RegEx") for this.
The pattern has a non-capturing group (?:...) that can determine if the start of the string ^ contains either three letters of any case: [a-zA-Z]{3} or | two digits \d{2}.
If either criterion is met, then the MsgBox will return True, otherwise, it returns False.
Sub test()
Dim RegEx As New RegExp, testString As String
testString = "53bcko390872"
With RegEx
.Pattern = "^(?:[a-zA-Z]{3}|\d{2})"
MsgBox .test(testString) 'will prompt True/False
End With
End Sub
You can replace the MsgBox line with something useful, such as
If .test(testString) [= True] Then...
Click Here for a live demo on the regex working (optional).
Note that you will need to set a reference to Microsoft VBScript Regular Expressions x.x