如何在字符串列表的末尾和开头添加一个字符？

Question

我有一个包含这些列表字符串的数组：

a -- b -- c 
d -- e -- f
g -- h -- i

我想要这个：

(a,b,c) , (d,e,f), (g,h,i)

这是我的代码：

'I iterate through the entire list to create the string
Dim valueChain As String = ""
Dim lista As New List(Of String)
For Each item In MyArrayList
    For Each subitem In item
        valueChain += subitem.ToString + " ,"
    Next

    ' I remove the last ,
    valueChain = valueChain.TrimEnd(",")
    valueChain = "(" + valueChain + ") ,"

Next

lista.Add(valueChain)

但我明白了：

(((a ,b ,c) ,d ,e ,f ) ,g ,h ,i ) ,

我怎样才能得到这个？ :

(a,b,c) , (d,e,f), (g,h,i)

Answer 1

您只添加了一次价值链。而是尝试将其添加到第一个循环中并在此之后清理 valueChain。

     Dim lista As New List(Of String)
          For Each item In MyArrayList
                Dim valueChain As String = ""

                For Each subitem In item
                    valueChain += subitem.ToString + ","
                Next

                valueChain = valueChain.TrimEnd(",")
                valueChain = "(" + valueChain + ")"

                lista.Add(valueChain)
            Next

您将在 lista 中获得 3 件物品。

Answer 2

我补充一下：

Dim lista As New List(Of String)
          For Each item In MyArrayList
                Dim valueChain As String = ""

                For Each subitem In item
                    valueChain += subitem.ToString + ","
                Next

                valueChain = valueChain.TrimEnd(",")
                valueChain = "(" + valueChain + ")"

                lista.Add(valueChain)
            Next

然后添加这个来创建字符串：

Dim char As String = ""
            For i As Integer = 0 To lista.Count - 1
                char+= lista(i) + " ,"
            Next

            'I remove the last ,
            char= char.TrimEnd(",")

Answer 3

首先，我建议您使用 & (&) 连接运算符而不是加号 (+)，因为 & 是专门为此目的而设计的。

现在开始你的代码。如果你希望它像你写的那样紧凑，你应该在添加子项目时删除 space：

valueChain &= subitem.ToString & ","

请注意，如果这已经是 String 的数组，则不需要 ToString。

然后，您在主数组的每次迭代中不断在链前添加括号 (。您应该在开始遍历子项之前附加括号，然后在其后附加右括号：

For Each item In MyArrayList
    'Append the opening bracket.
valueChain &= "("
    For Each subitem In item
        valueChain &= subitem.ToString & ","
    Next

    'Remove the last comma
    valueChain = valueChain.TrimEnd(",")

    'Append the closing bracket and the comma.
    valueChain &= "), "
Next

'Remove the last comma and space.
valueChain = valueChain.TrimEnd(", ")

lista.Add(valueChain)

希望对您有所帮助！

如何在字符串列表的末尾和开头添加一个字符？

How can I add a characters at the end and at the beginning of a string list?

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