Can't find the right way to parse a string

Question

Hi to all,
I am new to Lab-View, coming from a "C" background. I have spent all afternoon trying to get something to work, with no success. I am looking for a way to read files that are named sequentially, with a common prefix. For example:
"abc2004_001.tst", "abc2004_002.tst",... .
These file are not generated by LabView and the problem is that the file counter does not have a fixed width (can be 2, 3, 4, ... character wide) and the file prefix is alpha_numeric.
What I would like to do is to select the first file in the sequence and let LabView generate all other name, incrementing the sequence number, until a file-not-found.
I've tried using regular expression but cannot make it work when the file name prefix contains
a number.
Any suggestion...
Thanks!
MichelB

Answer 1

MichelB wrote in news:5065000000080000000BF00000-
[email protected]:
> Hi to all,
> I am new to Lab-View, coming from a "C" background. I have spent all
> afternoon trying to get something to work, with no success. I am
> looking for a way to read files that are named sequentially, with a
> common prefix. For example:
> "abc2004_001.tst", "abc2004_002.tst",... .
> These file are not generated by LabView and the problem is that the
> file counter does not have a fixed width (can be 2, 3, 4, ...
> character wide) and the file prefix is alpha_numeric.
> What I would like to do is to select the first file in the sequence
> and let LabView generate all other name, incrementing the sequence
> number, until a file-not-found.
> I've tried usin
g regular expression but cannot make it work when the
> file name prefix contains a number.
> Any suggestion...
> Thanks!
> MichelB
Suggestion 1:
Use the "Scan From String" function
(Function palette->String->Scan From String)
Wire your input string to "Input String"
Wire this string constant "%[^_]_%d" to "Format String"
Expand the outputs to get two outputs.
The format string does this (string is divided in three)
%[^_] Extract all characters which is not _
_ Match the _
%d Exctract a decimal number
Suggestion 2:
Use the "Match Pattern" function
(Function palette->String->Match Pattern)
with the string "[a-zA-Z0-9]_" as the "regular pattern" input
The "after substring" output should hold the number(+filename ending)
If you have an array with input file names (e.g. from the "List Directory"
file function) then you have to use a for or while loop.
Hope this helps.
Rolf