asked on Excel VBA: How to load whole text (CSV) file in memory and parse strings
Hello!
First at all ... please sorry for my English!
And I think it's have sense to load whole file in memory and then parse it.
How to do it?
2. XER file consist from block of date. Each block have 3 parts:
First line (started from "%T") of block is Table header. Second line ("%F") is Fields headers. And next rows contain data ("%R").
Example:
3. Each table have regular structure.
4. Fields sets in each table (text block) are different.
5. Values of data are variant (but stored in XER file as text)
6. XER file not contain blank rows or special data blocks separator.
7. Last row of XER file is "%E".
My plane is:
A. Parse XER file in memory row by row.
B. When new table ("%T") appears create new Sheet.
C. Then write fields headers ("%F") and rows ("%R")
2. Maybe if we deal with large data files (160 000 rows) have sence to load whole file (20 MB) into memory, split to tables (block of data) via RegExp and then parse block to rows (or somehow paste them into sheets as array).
3. How to determine total rows count for showing form with progress bar?
4. How to determine Excel version for setup rows limit? --> Global Const EXCEL_ROW_LIMIT = 65536 (or 1048576)
P.S. Now I have some parser (attached) but this one hav¿ slow performance (because in load procedure used approach "symbol by symbol"). Source of XERparser is Oracle Support web-site (access only by suscription). Parser description is here: http://www.plannertuts.com/tutorials/using-primaveras-xer-file-parser-import-wbs-from-excel-without-the-sdk-840/
Difference 2003/2007 versions of Parser is only setup "Global Const EXCEL_ROW_LIMIT = 65536 (or 1048576)" (as far as I know)
Excel 2003 compatible code needed
Any help will be high appreciated!
xerFileParserBuilder-2003-and-20.zip
First at all ... please sorry for my English!
Data file
I have CSV file (text file with TAB delimiters). It's a XER file used by Primavera P6 Professional v8 for import/export data.First task: How to load XER file into Workbook?
Mostly XER file size is not big: 0.5 – 3.3 MB (5200 – 17000 rows). Maximum filesize (seldom) is 20 MB (160 000 rows).And I think it's have sense to load whole file in memory and then parse it.
How to do it?
Next task is Parsing
1. XER file is a text file with TAB delimited columns.2. XER file consist from block of date. Each block have 3 parts:
First line (started from "%T") of block is Table header. Second line ("%F") is Fields headers. And next rows contain data ("%R").
Example:
%T RCATVAL
%F rsrc_catg_id rsrc_catg_type_id seq_num rsrc_catg_short_name rsrc_catg_name parent_rsrc_catg_id
%R 56 22 0 Yes Yes
%R 27968 22 0 Yes Yes
%R 28020 27776 10 Yes Description
%T NEXT_TABLE
%F new fields set
%R A B C
3. Each table have regular structure.
4. Fields sets in each table (text block) are different.
5. Values of data are variant (but stored in XER file as text)
6. XER file not contain blank rows or special data blocks separator.
7. Last row of XER file is "%E".
My plane is:
A. Parse XER file in memory row by row.
B. When new table ("%T") appears create new Sheet.
C. Then write fields headers ("%F") and rows ("%R")
Questions
1. What is more efficient method for split row (by TAB) to cells (when you don't know columns count, at least for first row "%F" of table)?2. Maybe if we deal with large data files (160 000 rows) have sence to load whole file (20 MB) into memory, split to tables (block of data) via RegExp and then parse block to rows (or somehow paste them into sheets as array).
3. How to determine total rows count for showing form with progress bar?
4. How to determine Excel version for setup rows limit? --> Global Const EXCEL_ROW_LIMIT = 65536 (or 1048576)
P.S. Now I have some parser (attached) but this one hav¿ slow performance (because in load procedure used approach "symbol by symbol"). Source of XERparser is Oracle Support web-site (access only by suscription). Parser description is here: http://www.plannertuts.com/tutorials/using-primaveras-xer-file-parser-import-wbs-from-excel-without-the-sdk-840/
Difference 2003/2007 versions of Parser is only setup "Global Const EXCEL_ROW_LIMIT = 65536 (or 1048576)" (as far as I know)
Resume
There is base XER Parser (from Oracle) and my task is to optimize performance for load date.Excel 2003 compatible code needed
Any help will be high appreciated!
xerFileParserBuilder-2003-and-20.zip
Microsoft ExcelProductivity AppsDocument Management
Last Comment
Igor Spryzhkov
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ASKER
Thanks! Very substantial links! HQ answer!
ASKER
In e-book "VBA and macros : Microsoft Excel 2010 / Bill Jelen, Tracy Syrstad." there is good example
Sub ReadTxtLines()
' Read Entire TXT to Memory and Parse
' Submitted by Suat Mehmet Ozgur of Istanbul, Turkey. Suat develops applications in Excel,
' Access, and Visual Basic.
' This sample takes a different approach to reading a text file. Instead of reading one record
' at a time, the macro loads the entire text file into memory in a single string variable. The
' macro then parses the string into individual records. The advantage of this method is that
' you access the file on disk only one time. All subsequent processing occurs in memory and
' is very fast:
'No need to install Scripting Runtime library since we used late binding
Dim sht As Worksheet
Dim fso As Object
Dim fil As Object
Dim txt As Object
Dim strtxt As String
Dim tmpLoc As Long
'Working on active sheet
Set sht = ActiveSheet
'Clear data in the sheet
sht.UsedRange.ClearContents
'File system object that we need to manage files
Set fso = CreateObject(“Scripting.FileSystemObject”)
'File that we like to open and read
Set fil = fso.GetFile("c:\test.txt")
'Opening file as a TextStream
Set txt = fil.OpenAsTextStream(1)
'Reading file include into a string variable at once
strtxt = txt.ReadAll
'Close textstream and free the file. We don’t need it anymore.
txt.Close
'Find the first placement of new line char
tmpLoc = InStr(1, strtxt, vbCrLf)
'Loop until no more new line
Do Until tmpLoc = 0
'Use A column and next empty cell to write the text file line
sht.Cells(sht.Rows.Count, 1).End(xlUp).Offset(1).Value = _
Left(strtxt, tmpLoc - 1)
'Remove the parsed line from the variable that we stored file include
strtxt = Right(strtxt, Len(strtxt) - tmpLoc - 1)
'Find the next placement of new line char
tmpLoc = InStr(1, strtxt, vbCrLf)
Loop
'Last line that has data but no new line char
sht.Cells(sht.Rows.Count, 1).End(xlUp).Offset(1).Value = strtxt
'It will be already released by the ending of this procedure but
' as a good habit, set the object as nothing.
Set fso = Nothing
End Sub
Also at first hand, you mention Code to be Excel 2003 compatible however Excel 2003 support only 65536 rows and you mention rows could easily go to 160000 hence presume you will need at least Excel 2007 is this a problem ? if 2003 we can put the overflow on 65536 to subseuent worksheets would this be an option for you if you need to stick to 2003 ?
Last but not least can you post the longest XER file you have so we can build the macro around it ?
gowflow