Question

如何计算vb.net中字符串或整数数组中存在的重复数字？

Dim a as string = "3,2,3"

从上面的“a”变量我希望计数“3”为2（我的意思是3存在2次）和“2”为“1”。那么我如何在vb.net中制作它?????

实际上我将从sql数据库中获取上面的字符串“a”。所以我不知道那里有哪些数字。这就是我在这里问的原因。

Answer 1

如果您的示例中有一个字符串，请根据您的分隔符将其拆分;然后你可以使用GroupBy Linq查询：

Dim source = "3,2,3".Split(","c)

Dim query = From item In source
            Group By item Into Count()

For Each result In query
    Console.WriteLine (result)
Next

' output
' { item = 3, Count = 2 }
' { item = 2, Count = 1 }

Answer 2

使用Dictionary的另一个选项：

java.io.File

输出：

    Dim a As String = "3,2,3"

    Dim counts As New Dictionary(Of String, Integer)
    For Each value As String In a.Split(",")
        If Not counts.ContainsKey(value) Then
            counts.Add(value, 1)
        Else
            counts.Item(value) = counts.Item(value) + 1
        End If
    Next

    For Each kvp As KeyValuePair(Of String, Integer) In counts
        Debug.Print("Value: " & kvp.Key & ", Count: " & kvp.Value)
    Next

Answer 3

你已经有了一些很好的答案可供选择，但我认为你会对单线解决方案感兴趣。

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解释发生了什么：

Module Module1 Sub Main() Dim str() As String = "1,2,1,2,3,1,0,1,4".Split(","c) str.Distinct().ToList().ForEach(Sub(digit) Console.WriteLine("{0} exists {1}", digit, str.Count(Function(s) s = digit))) Console.ReadLine() End Sub End Module Distinct() - 返回数组中所有唯一项的str.对象
IEnumerable ToList() - 将.对象变为IEnumerable
List<T> ForEach() - 通过.进行迭代
- List<T> - 定义要对每个元素执行的Action委托。每次迭代时，每个元素都被命名为数字。
- 您应该知道Sub(digit)正在做什么
- Console.WriteLine() Count() - 将每次出现一个满足条件的数字
  - str. - 定义一个Func委托，用于计算数组中每次出现的数字。在计数迭代期间，Function(s) s = digit中的每个元素都存储在变量str()中，如果它与s中的数字变量匹配，则会计入

结果：

Sub(digit)

Answer 4

Dim count2 as integer = 0
Dim count3 as integer = 0    
For Each c As Char in a
 if c = "3"
      count3 += 1
 else if c = "2"
      count2 += 1
 end if
Next
console.writeline(count2)
console.writeline(count3)

我猜，听起来有点像家庭作业

如何在vb.net中查找和计算字符串数组中的重复数字？

4 个答案: