Indexed files - Printable Version

CONST Length_of_Data = 30 'set a constant length for your record size OPEN "temp.txt" FOR RANDOM AS #1 LEN = Length_of_Data 'Set that length for the file you're working with DIM My_Junk AS STRING * Length_of_Data 'And create a string to hold your data the same size. 'Now, let's PUT some data into that file My_Junk = "Hello World. #1 Record." PUT #1, 1, My_Junk My_Junk = "My name is Steve. #2 Record." PUT #1, 2, My_Junk My_Junk = "This is a demo! #3 Record." PUT #1, 3, My_Junk My_Junk = "Hiyas Phil! #4 Record." PUT #1, 4, My_Junk My_Junk = "I need coffee! #5 Record." PUT #1, 5, My_Junk My_Junk = "I'm finished here. #6 Record." PUT #1, 6, My_Junk 'Did you notice where we use the record number as the 2nd element in that PUT statement? 'Now, let's get that random data back and print it ot the screen. 'First, in order from start to finish... FOR i = 1 TO 6 GET #1, i, My_Junk 'Notice that we GET the record via that 2nd parameter as well PRINT i, My_Junk NEXT PRINT PRINT DO INPUT "Now, which record would you like to pull out randomly? =>"; record IF record = 0 OR record > 6 THEN END GET #1, record, My_Junk PRINT "Record #"; record; ":"; My_Junk LOOP 'And that's all there is to it!

Code: (Select All)

_Title "Random Access text file" ' bplus 2023-11-04

Dim Shared MyFile$ ' name of text/data file being a text file you can use any editor to edit

MyFile$ = "Test File Index Access.txt"

Dim Shared NRecs ' Number of records

NRecs = 1

ReDim Shared MyArr$(1 To NRecs)

Width _DesktopWidth * .9 / 8

LoadFile

Dim As Long edit, rec

edit = -1

rec = 1

While edit

    Color 9

    Print

    Print "Rec Number:";

    Color 15

    Print rec

    Color 9

    Print "  Rec line: ";

    Color 15

    Print MyArr$(rec)

    Color 9

    Print

    Print "Enter number for record to read,"

    Print "Don't start numbers with 0."

    Print "enter non number to edit line,"

    Print "enter esc to quit..."

    Print

    Color 15

    Input u$

    If u$ <> "" Then

        If Asc(u$) = 27 Then

            edit = 0: Exit While

        ElseIf InStr("123456789", Left$(u$, 1)) Then

            test = Val(u$)

            If test > 0 Then

                If test >= NRecs Then enlargeMyArr test

                rec = test

            Else

                Beep

            End If

        ElseIf _Trim$(u$) <> "" Then

            MyArr$(rec) = u$

        End If

    End If

Wend

SaveFile

End



Sub enlargeMyArr (recs)

    If recs > UBound(MyArr$) Then ReDim _Preserve MyArr$(1 To recs): NRecs = recs

End Sub



' first thing to do for processing file data

Sub LoadFile ' loads file to working array with file lines as records

    If _FileExists(MyFile$) Then

        rec = 0

        Open MyFile$ For Input As #1

        While Not EOF(1)

            Line Input #1, r$

            rec = rec + 1

            If rec > UBound(MyArr$) Then ReDim _Preserve MyArr$(1 To rec)

            MyArr$(rec) = r$

        Wend

        Close #1

        NRecs = rec

    End If

End Sub



' last thing to do when done processing file data

Sub SaveFile ' saves myarr$ to file

    ' save a backup to MyFile$ in case something happens

    If _FileExists(MyFile$) Then

        Open MyFile$ For Input As #1

        Open "MyOldFileBackup.txt" For Output As #2

        While Not EOF(1)

            Line Input #1, r$

            Print #2, r$

        Wend

        Close

    End If

    Open MyFile$ For Output As #1

    For i = 1 To NRecs

        Print #1, MyArr$(i)

    Next

    Close #1

End Sub