vb loop extraction txt specified

Answer 1

The following are some common methods to loop and extract the specified content of the txt-file in the visual basic:

** 1. Read and extract by line cycle **
1. Basic line reading
- First, you need to open the file. For example, you can use the `Freefile` function to get a free file number, and then use `Open "file path" For Input As #file number` to open the file for reading.
- Use the loop of `Do Until Husband (file number)`, where the `Husband` function is used to determine whether the end of the file has been reached. Inside the loop, use `Line Input #file number, variable name` to read the file contents line by line into a string variable.
2. Extracting the specified content
- For each line of content read, you can use a string function such as `InStr` to determine whether the line contains a specified keyword (such as Chinese keywords). If the keyword was included, the row could be further processed or the relevant data could be extracted according to the requirements. For example:
```vb
Dim FileNum As Integer
Dim LineContent As String
FileNum = FreeFile
Open "D:/test.txt" For Input As #FileNum
Do Until EOF(FileNum)
Line Input #FileNum, LineContent
If InStr(Linecontent, "specify keyword") <> 0 Then
'Here, you can extract relevant data, such as splitting strings according to the format.
End If
Loop
Close FileNum
```

** 2. After reading the array, extract it in a loop **
1. Read file contents into array
- You can first read the entire file content into an array. For example, define a function to implement:
```vb
Function ReadTextFileToArray(strFileName As String) As Variant
Dim strText As String
Dim lines() As String
Dim dataArray() As Variant
Dim i As Long, j As Long
'Read the entire file
strText = ReadTextFromFullFile(strFileName)
If Trim(strText) = "" Then
ReadTextFileToArray = Array()
Exit Function
End If
lines = Split(strText, vbCrLf)
Dim columns() As String
columns = Split(lines(0), "|")
ReDim dataArray(0 To UBound(lines), 0 To UBound(columns))
For i = LBound(lines) To UBound(lines)
'uses| Divide each row to get an array of column values
columns = Split(lines(i), "|")
For j = LBound(columns) To UBound(columns)
dataArray(i, j) = columns(j)
Next j
Next i
ReadTextFileToArray = dataArray
End Function
```
2. Loop Array to extract the specified content
- For the resulting array, you can loop through the rows and columns of the array to find the elements that contain the specified content. For example:
```vb
Dim dataArray As Variant
dataArray = ReadTextFileToArray("D:/test.txt")
For i = LBound(dataArray, 1) To UBound(dataArray, 1)
For j = LBound(dataArray, 2) To UBound(dataArray, 2)
If dataArray(i, j) = "specify content" Then
'perform related operations, such as extracting data from the row or column
End If
Next j
Next i
```
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