[2005] Finding possible matches

[Troy Lundin]

Say I have a textfile with the following words:

Apple
Bake
Bike
Cake
Lemon
Water


I want to find all the four letter words with the second letter of 'a' and the fourth letter of 'e'. Something like '_a_e'

The matches would be Bake and Cake. How would I find the matches though? I do not know what to search for. I have add the list to a String() and have also tried a List(Of String), but cannot figure it out?

Any help is appreciated. Thanks, Troy.

[stanav]

Regex is your friend for doing stuffs like this. The pattern for finding 4 letter words is "\b[a-zA-Z]{4}\b", however, since you only want 4 letter words that have a in the 2nd position and e in the last position, you need to modify the pattern. Let me give a quick explanation:
[a-zA-Z]{1} : match any letter in the groups a-z and A-Z exactly 1 occurence
[a-zA-Z]{1}a : same as above plus followed by an a
[a-zA-Z]{1}a[a-zA-Z]{1}e : match (any letter)a(any letter)e
Add \b to the beginning and the end of the pattern and you have what you need as in the code below.

Dim input As String = "Apple Bake Bike Cake Lemon Water nightmare scare are"
        Dim pattern As String = "\b[a-zA-Z]{1}a[a-zA-Z]{1}e\b"
        Dim rgx As System.Text.RegularExpressions.Regex
        Dim matches As System.Text.RegularExpressions.MatchCollection
        matches = rgx.Matches(input, pattern)
        'View output
        Dim output As String = String.Empty
        For Each m As System.Text.RegularExpressions.Match In matches
            output &= m.Value & " "
        Next
        MessageBox.Show(output)

[Troy Lundin]

Regular Expressions had always intimidated me, but your example has put it into perspective.

I will try it out. Thanks.