Vista - find last non-empty line

Hi,

I have the following situation: I need to read the last line of a plain-
text file. But it can contain emtpy lines. So I am looking for a way to
check if a line is empty. I could do a top-to-bottom analysis of the
file and use ReadLine for every line, but I was wondering whether there
is a faster way. Like read the entire file, and then read it from the
end somehow.

tia
arno

"arno" <noreplyAThighiqDOTnl@xxxxxx> wrote in message
news:MPG.23dddf38da680d6a98968b@xxxxxxOne way or another you pretty much have to read the entire file to get the
last non-blank line. If it is very large you will wind up doing the
blank/non-blank test lots of time if you read through line by line. If you
read the whole file in at one time (possibly resulting in less time taken up
by reading the file) into an array and process this in reverse order, you
will likely do fewer comparisons. It is not really possible to determine
where the trade off is. On top of it all, consider two huge files containing
all blank lines but one: the first line in one file and the last line in the
other.

BTW, the fastest way to read in an entire text file is to use the .read
method, and specify a number of bytes equal to the size of the file. For
large files this can be significantly more efficient than .readall, because
that buffers the input and performs string concatenation.

I'd suggest that you select your algorithm based on its simplicity. If it
takes too long, you could then look for ways to tweak it.

How you check lines to see if they are empty, well, that depends on what you
mean by an empty line. Does it mean a line containing no characters (i.e. a
line of length - zero), containing any number of blanks, or containing any
number of "whitespace" characters (blank, tab, vertical tab?).

/Al

"arno" <noreplyAThighiqDOTnl@xxxxxx> wrote in message
news:MPG.23dddf38da680d6a98968b@xxxxxxYou can use the 'VBScript.RegExp' object to do this. See below for an
example.

Dim oRegEx, oMatches, oFSO, sLastNonEmptyLine, sFile, sText
Set oRegEx = CreateObject("VBScript.RegExp")
Set oFSO = CreateObject("Scripting.FileSystemObject")

sFile = "C:\Test.txt"

oRegEx.MultiLine = True
oRegEx.Global = True
oRegEx.Pattern = "^[^\n\r\b]+$"

sText = oFSO.OpenTextFile(sFile, 1).ReadAll

Set oMatches = oRegEx.Execute(sText)
sLastNonEmptyLine = oMatches(oMatches.Count - 1)

MsgBox sLastNonEmptyLine, vbInformation, "Last Non-Empty Line"

s = TS.ReadAll
A = Split(s, vbCrLf)
For i = Ubound(A) to 0 Step -1
s = Trim(A(i))
If len(s) > 0 Then
MsgBox "Last line is: " & s
Exit For
End If
Next

The above adds an extra Trim operation just
to make sure you don't read a line with a space
as the last line. You may not need that part.

Interesting input, tx all

arno

In article <O6kKrmeeJHA.5748@xxxxxx>, mayaXXyana@xxxxxx
says...>