EXCEL-VBA Return highest value from a find function from a txt file VBA

Question

Here is the problem:

-I have a text file that contains a lot of data but I have to extract the line containing the string "pressure: (values)" . The file has lots of this string and I wanted to extract the highest values after the word pressure. Here are some sample contents from the file: - pressure: 10.1101 - pressure: 20.1102 - pressure: 20.1020

The number of occurrence of "pressure: " is not fixed.

I have already figure out some needed function to make this happen (just copied and edited some script found in the net). But I don't know how to store the matched values (perhaps store in a array?) then apply max function to return the highest value. Will appreciate any input.

Other approach to attain the desired task is also welcome.

Here is my script:

Sub search()
Const ForReading = 1
Dim FSO, FileIn, strTmp

Set FSO = CreateObject("Scripting.FileSystemObject")
Set FileIn = FSO.OpenTextFile("D:\data.txt", ForReading)

Do Until FileIn.AtEndOfStream
    strTmp = FileIn.ReadLine
    If Len(strTmp) > 0 Then 'read if not blank
        If InStr(1, strTmp, "pressure:", vbTextCompare) > 0 Then 'find function
            x = Mid(strTmp, 10, 7) 'to extract the numeric values only
            MsgBox x 'just for checking if value of x is correct

            'add function that will return the highest value
            'WorksheetFunction.Max (x)

        End If

    End If
Loop

FileIn.Close

End Sub

Answer 1

If you only want the single largest value of pressure then simply keep track of the largest value found so far, and update it if a larger value is found.

Here's your code refactored with a few other minor issues addressed (changes marked <--- )

Sub search()
    Const ForReading = 1
    '<--- Use specific data types rather than variant
    Dim FSO As Object
    Dim FileIn As Object
    Dim strTmp As String
    Dim KeyWord As String
    Dim i As Long, j As Long
    Dim x As Double
    Dim MaxX As Double

    MaxX = -4.94065645841247E-324 '<-- initialise to lowest possible value
    KeyWord = "pressure:" ' <--- generalise the function
    Set FSO = CreateObject("Scripting.FileSystemObject")
    Set FileIn = FSO.OpenTextFile("D:\data.txt", ForReading)

    Do Until FileIn.AtEndOfStream
        strTmp = FileIn.ReadLine
        If Len(strTmp) > 0 Then 'read if not blank
            i = InStr(1, strTmp, KeyWord, vbTextCompare)
            If i Then  'find function
                ' <-- cope with possibility Pressure is not at start of string 
                '     and may have trailing data
                strTmp = Trim$(Mid$(strTmp, i + Len(KeyWord)))
                i = InStr(strTmp, " ")
                If i Then
                    strTmp = Trim$(Left$(strTmp, i - 1))
                End If
                x = Val(strTmp) 'to extract the numeric values only
                MsgBox x 'just for checking if value of x is correct

                'add function that will return the highest value
                If x > MaxX Then MaxX = x
            End If

        End If
    Loop

    FileIn.Close
    MsgBox "Max presseure is " & MaxX
End Sub