如何修复由vb.net中的array.contains方法找到的元素的索引 [英] how to retieve the index of an element which is found by array.contains method in vb.net

问题描述

我有一个数组中大量字符串元素的列表，我使用包含函数来检查它是否包含该元素。它工作正常。现在我想了解元素的索引/位置。假设数组是

 dim s  as   string （）= {  first，  second，  third} 
和字符串 
 
 dim l  as   string  =   third 
 method 
 
 dim b  as  boolean = s.Contains（l，StringComparer.CurrentCultureIgnoreCase）
 flag 
 
  if （b）然后
 messagebox.show（ 存在）
 end  if  

解决方案

使用 A. rray.IndexOf 。使用此方法，您甚至不需要包含： IndexOf 返回 -1 如果该项目不存在：

  Dim  s 作为 字符串（）= {  first，  second，  third} 
  Dim  l 作为 字符串 =   third 
  Dim  i  As   Integer  = Array.IndexOf（s，l）
 如果 i> =  0  然后 
控制台.WriteLine（ 它存在于索引 + i.ToString（））
 结束 如果 

重要：如果要使用 StringComparer.CurrentCultureIgnoreCase ，则不能使用上述内容;在这种情况下你必须使用 FindIndex ：

  Dim  i  As   Integer  = Array.FindIndex（s，函数（x  As   String ）x.Equals（l，StringComparison .CurrentCultureIgnoreCase））

i have a list of large number of string elements in array and i am using contains function to check if it contains that element. it is working fine. Now i want to get to know the index/position of element. suppose the array is

dim s as string() = {"first", "second","third"}
and the string

dim l as string = "third"
method

dim b as boolean = s.Contains(l, StringComparer.CurrentCultureIgnoreCase)
flag

if (b) Then
messagebox.show("It exists") 
end if

解决方案

Use Array.IndexOf. With this method, you don't even need Contains: IndexOf returns -1 if the item doesn't exist:

Dim s As String() = {"first", "second", "third"}
Dim l As String = "third"
Dim i As Integer = Array.IndexOf(s, l)
If i >= 0 Then
    Console.WriteLine("it exists at index " + i.ToString())
End If

Important: if you want to use StringComparer.CurrentCultureIgnoreCase, then you cannot use the above; you'll have to use FindIndex in that case:

Dim i As Integer = Array.FindIndex(s, Function(x As String) x.Equals(l, StringComparison.CurrentCultureIgnoreCase))

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