vb.net：从“中提取字符串”；a123“；至；b123“；

我有一个字符串如下所示：

SODJFOISDF sdofij sodiosifosf fsdi a123 sdfoi sdofi osdi foi sdofd oi b123 SDFOIJSDOIFSDDIOSDOIFSOIFSFDOFJSSFDOJI

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如何提取a123到b123的所有内容？

如果您的模式像

a123

一样简单，那么简单的字符串操作就足够了：

Dim s As String = "sodjfoisdfsdf sdofij sodiosifosf fsdi a123 sdfoi sdofi osdi foi sdofd oi b123 sdfoijsfdoifsdiosfdoifsoifsdofjssfdoji"

Dim startIndex As Integer = s.IndexOf("a123") + "a123".Length
Dim endIndex As Integer = s.IndexOf("b123")

Dim result = s.Substring(startIndex, endIndex - startIndex)

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您可以使用文本解析函数来查找标记的开始和结束位置

例如：

Dim s As String = "sodjfoisdfsdf sdofij sodiosifosf fsdi a123 sdfoi sdofi osdi foi sdofd oi b123 sdfoijsfdoifsdiosfdoifsoifsdofjssfdoji"
Dim startToken As String = "a123"
Dim endToken As String = "b123"
Dim startTokenPosition As Integer = s.IndexOf(startToken)
Dim endTokenPosition As Integer = s.IndexOf(endToken)
'Validate both startToken and endToken were found...
Dim mysubstring As String = s.Substring(startTokenPosition + startToken.Length, endTokenPosition - startTokenPosition - startToken.Length)