比较两个字符串并找到字母位置匹配的位置

Question

I want to do a bitwise and on two strings so that:

Given:

 Dim word As String = "abcd"
 Dim temp As String = "a-d-"

I want to return only the 'a'

Given:

 Dim word As String = "abcd"
 Dim temp As String = "a--d"

I want to return only the 'a--d'

I have tried intersect, but it only finds characters in one string that match the characters in the other regardless of position.

I've used the '-' to represent spaces here.

Any suggestions would be appreciated.

Answer 1

This will handle strings with mis-matched lengths:

Public Function CheckMask(ByVal word As String, ByVal mask As String) As String
    Dim wordChars() As Char = word.ToCharArray()
    Dim maskChars() As Char = mask.ToCharArray()

    Dim i As Integer = 0       
    While i < wordChars.Length AndAlso i < maskChars.Length
        If wordChars(i) <> maskChars(i) Then wordChars(i) = " "c
        i = i + 1
    End While

    'If string lengths are equal or the mask is longer, we're done
    'If the word is longer, need to set remaining characters to " "
    While i < wordChars.Length
        wordChars(i) = " "c
    End While

    Return New String(wordChars)
End Function

Answer 2

Dim Res As String = ""    
For i = 0 To Math.Min(StrA.Length, StrB.Length) - 1
    If StrA(i) = StrB(i) Then Res &= StrA(i) Else Res &= " "
Next
Return Res

This basically loops to the end of the shorter one of the two strings. If the letters at a given position match the letter is added to the result, else a space is added.

Answer 3

    Dim sFirstWord As String = "qwerty"
    Dim sSecndWord As String = "qseftg"
    Dim sResult As String = ""

    For i As Integer = 0 To Math.Min(sFirstWord.Length, sSecndWord.Length) - 1
        If sFirstWord(i) = sSecndWord(i) Then
            sResult &= sFirstWord(i)
        Else
            sResult &= " "
        End If
    Next

sResult will hold: "qet "