Select text between key words

问题

This is a follow on question to Select block of text and merge into new document

I have a SGM document with comments added and comments in my sgm file. I need to extract the strings in between the start/stop comments so I can put them in a temporary file for modification. Right now it's selecting everything including the start/stop comments and data outside of the start/stop comments.

Dim DirFolder As String = txtDirectory.Text
Dim Directory As New IO.DirectoryInfo(DirFolder)
Dim allFiles As IO.FileInfo() = Directory.GetFiles("*.sgm")
Dim singleFile As IO.FileInfo
Dim Prefix As String
Dim newMasterFilePath As String
Dim masterFileName As String
Dim newMasterFileName As String
Dim startMark As String = "<!--#start#-->"
Dim stopMark As String = "<!--#stop#-->"
searchDir = txtDirectory.Text
Prefix = txtBxUnique.Text

For Each singleFile In allFiles
    If File.Exists(singleFile.FullName) Then
        Dim fileName = singleFile.FullName
        Debug.Print("file name : " & fileName)
        ' A backup first    
        Dim backup As String = fileName & ".bak"
        File.Copy(fileName, backup, True)

        ' Load lines from the source file in memory
        Dim lines() As String = File.ReadAllLines(backup)

        ' Now re-create the source file and start writing lines inside a block
        ' Evaluate all the lines in the file.
        ' Set insideBlock to false
        Dim insideBlock As Boolean = False
        Using sw As StreamWriter = File.CreateText(backup)
            For Each line As String In lines
                If line = startMark Then
                    ' start writing at the line below
                    insideBlock = True
                    ' Evaluate if the next line is <!Stop>
                ElseIf line = stopMark Then
                    ' Stop writing
                    insideBlock = False
                ElseIf insideBlock = True Then
                    ' Write the current line in the block
                    sw.WriteLine(line)
                End If
            Next
        End Using
    End If

Next

This is the example text to test on.

<chapter id="Chapter_Overview"> <?Pub Lcl _divid="500" _parentid="0"> 
<title>Learning how to gather data</title>
<!--#start#-->
<section>
<title>ALTERNATE MISSION EQUIPMENT</title>
<para0 verdate="18 Jan 2019" verstatus="ver">
<title>
<applicabil applicref="xxx">
</applicabil>Three-Button Trackball Mouse</title>
<para>This is the example to grab all text between start and stop comments. 
</para></para0>
</section>
<!--#stop#-->

Things to note: the start and stop comments ALWAYS fall on a new line, a document can have multiple start/stop sections

I thought maybe using a regex on this

(<section>[\w+\w]+.*?<\/section>)\R(<\?Pub _gtinsert.*>\R<pgbrk pgnum.*?>\R<\?Pub /_gtinsert>)*

Or maybe use IndexOf and LastIndexOf, but I couldn't get that working.

回答1:

You can read the entire file and split it into an array using the string array of {"", ""} to split, into this

Element 0: Text before ""
Element 1: Text between "" and ""
Element 2: Text after ""

and take element 1. Then write it to your backup.

Dim text = File.ReadAllText(backup).Split({startMark, stopMark}, StringSplitOptions.RemoveEmptyEntries)(1)
Using sw As StreamWriter = File.CreateText(backup)
    sw.Write(text)
End Using

Edit to address comment

I did make the original code a little compact. It can be expanded out into the following, which allows you to add some validation

Dim text = File.ReadAllText(backup)
Dim split = text.Split({startMark, stopMark}, StringSplitOptions.RemoveEmptyEntries)
If split.Count() <> 3 Then Throw New Exception("File didn't contain one or more delimiters.")
text = split(1)
Using sw As StreamWriter = File.CreateText(backup)
    sw.Write(text)
End Using

来源：https://stackoverflow.com/questions/58561174/select-text-between-key-words

标签

vb.net

text-extraction