統計英文字串中字母個數
今天在論壇中看到一個不算難的問題，是想要能統計出英文單字的個數。由於一開始誤解了其意思，就變成了統計英文字串中字母的個數了。既然都寫了，隨手記錄一下。這問題有很多解法，這邊隨手寫了三個，也希望大家能提供一些不一樣的寫法。
解法一
採用陣列搭配ASCII編碼來記錄出現次數
Sub Test(ByVal inputString As String)
Dim symbolCount(25) As Integer
Dim startAscii As Integer = Asc("a"c)
Dim maxSymbolIdx As Integer
Dim idx As Integer
For Each c As Char In inputString
idx = Asc(c) - startAscii
symbolCount(idx) = symbolCount(idx) + 1
If symbolCount(idx) > symbolCount(maxSymbolIdx) Then
maxSymbolIdx = idx
End If
Next
For idx = 0 To 25
Console.Write(Chr(startAscii + idx) & ": ")
Console.WriteLine(symbolCount(idx).ToString)
Next
Console.WriteLine()
Console.Write("Max Count Symbol: ")
Console.WriteLine(Chr(startAscii + maxSymbolIdx))
End Sub
解法二
Sub Test(ByVal inputString As String)
Dim chars() As Char = inputString.ToCharArray
Array.Sort(chars)
Dim maxChar As Char
Dim maxCount As Integer = 0
Dim preChar As Char = chars(0)
Dim count As Integer = 0
For Each c As Char In chars
If preChar <> c Then
Console.Write(preChar & ": ")
Console.WriteLine(count.ToString)
preChar = c
count = 0
End If
count += 1
If count > maxCount Then
maxCount = count
maxChar = c
End If
Next
Console.WriteLine()
Console.Write("Max Count Symbol: ")
Console.WriteLine(maxChar)
End Sub
解法三
採用Linq的Group By與Order By來做
Sub Test(ByVal inputString As String)
Dim chars() As Char = inputString.ToCharArray
Dim linq = From c In chars Group c By c Into Group Order By Group.Count Descending Select New With {.Symbol = c, .Count = Group.Count}
For Each item In linq
Console.WriteLine(item.Symbol & ": " & item.Count)
Next
Console.WriteLine()
Console.Write("Max Count Symbol: ")
Console.WriteLine(linq(0).Symbol)
End Sub