Simple "Not" Match?

1 Nov 2006 9:44 PM

xeroxero

I have code that recursively traverses a directory and writes to a
file. I would like to ignore any directory or file that matches a
pattern that is in a string array ( '*.obj' , 'doc*.*' ). Can anyone
show an example of how to do that?

Thanks.

2 Nov 2006 3:54 AM

Carl Daniel [VC++ MVP]

xeroxero wrote:

> I have code that recursively traverses a directory and writes to a
> file. I would like to ignore any directory or file that matches a
> pattern that is in a string array ( '*.obj' , 'doc*.*' ). Can anyone
> show an example of how to do that?

Start from here:

http://www.codeproject.com/cs/files/FileSystemEnumerator.asp

Then use a regular expression to reject items that you don't want to
include. Something like this:

using System.Text.RegularExpressions;

void SomeMethod(string path)
{
    Regex reject = new Regex(@"^(.*\.obj)|(doc.*)$");

    using (FileSystemEnumerator fse = new FileSystemEnumerator(path,
"*",true))
    {
        foreach (FileInfo fi in fse.Matches())
        {
            if (reject.IsMatch(fi.Name))
                continue;

            // this file matches - do something with it.
        }
    }
}

-cd

2 Nov 2006 4:23 PM

xeroxero

Great, thanks!

On Wed, 1 Nov 2006 19:54:17 -0800, "Carl Daniel [VC++ MVP]"
<cpdaniel_remove_this_and_nospam@mvps.org.nospam> wrote:

Show quote

>xeroxero wrote:
>> I have code that recursively traverses a directory and writes to a
>> file. I would like to ignore any directory or file that matches a
>> pattern that is in a string array ( '*.obj' , 'doc*.*' ). Can anyone
>> show an example of how to do that?
>
>Start from here:
>
>http://www.codeproject.com/cs/files/FileSystemEnumerator.asp
>
>Then use a regular expression to reject items that you don't want to
>include. Something like this:
>
>using System.Text.RegularExpressions;
>
>void SomeMethod(string path)
>{
>    Regex reject = new Regex(@"^(.*\.obj)|(doc.*)$");
>
>    using (FileSystemEnumerator fse = new FileSystemEnumerator(path,
>"*",true))
>    {
>        foreach (FileInfo fi in fse.Matches())
>        {
>            if (reject.IsMatch(fi.Name))
>                continue;
>
>            // this file matches - do something with it.
>        }
>    }
>}
>
>-cd
>

3 Nov 2006 2:16 PM

Ben Voigt

Show quote

"Carl Daniel [VC++ MVP]" <cpdaniel_remove_this_and_nospam@mvps.org.nospam>
wrote in message news:%23Ik3SKj$GHA.4676@TK2MSFTNGP04.phx.gbl...
> xeroxero wrote:
>> I have code that recursively traverses a directory and writes to a
>> file. I would like to ignore any directory or file that matches a
>> pattern that is in a string array ( '*.obj' , 'doc*.*' ). Can anyone
>> show an example of how to do that?
>
> Start from here:
>
> http://www.codeproject.com/cs/files/FileSystemEnumerator.asp
>
> Then use a regular expression to reject items that you don't want to
> include. Something like this:
>
> using System.Text.RegularExpressions;
>
> void SomeMethod(string path)
> {
>    Regex reject = new Regex(@"^(.*\.obj)|(doc.*)$");
>
>    using (FileSystemEnumerator fse = new FileSystemEnumerator(path,
> "*",true))
>    {
>        foreach (FileInfo fi in fse.Matches())
>        {
>            if (reject.IsMatch(fi.Name))
>                continue;

Unless I miss my guess this won't actually skip directories that match...

Show quote

>
>            // this file matches - do something with it.
>        }
>    }
> }
>
> -cd
>
>

4 Nov 2006 3:19 PM

Carl Daniel [VC++ MVP]

Ben Voigt wrote:
Show quote

> "Carl Daniel [VC++ MVP]"
> <cpdaniel_remove_this_and_nospam@mvps.org.nospam> wrote in message
> news:%23Ik3SKj$GHA.4676@TK2MSFTNGP04.phx.gbl...
>> xeroxero wrote:
>>> I have code that recursively traverses a directory and writes to a
>>> file. I would like to ignore any directory or file that matches a
>>> pattern that is in a string array ( '*.obj' , 'doc*.*' ). Can anyone
>>> show an example of how to do that?
>>
>> Start from here:
>>
>> http://www.codeproject.com/cs/files/FileSystemEnumerator.asp
>>
>> Then use a regular expression to reject items that you don't want to
>> include. Something like this:
>>
>> using System.Text.RegularExpressions;
>>
>> void SomeMethod(string path)
>> {
>>    Regex reject = new Regex(@"^(.*\.obj)|(doc.*)$");
>>
>>    using (FileSystemEnumerator fse = new FileSystemEnumerator(path,
>> "*",true))
>>    {
>>        foreach (FileInfo fi in fse.Matches())
>>        {
>>            if (reject.IsMatch(fi.Name))
>>                continue;
>
> Unless I miss my guess this won't actually skip directories that
> match...

Yes, that's true - I missed the OPs statement that he wanted to skip files
OR directories that match. To be 100% accurate applying to individual
directories:

replace the simple if (reject.IsMatch(fi.Name))

with something like...

string[] parts = fi.FullName.Split(Path.PathSeparator);
if (parts.Length < 2)
    continue;
string[] names = parts[1].Split(Path.DirectorySeparatorChar);
bool matched = false;
foreach (string name in names)
{
    if (reject.IsMatch(name))
    {
        matched = true;
        break;
    }
}
if (matched)
    continue;

.... I'm sure with enough fiddling a regex could be constructed that handles
it all.   I'm not sure using such a regex would actually be faster since it
could involve a lot of backtracking during regex matching which might take
as much time as just splitting the string up.

Of course, the best way to deal with directories in this case would be to
modify FileSystemEnumerator to also accept a list of directory
names/filespecs to exclude, so the entire visitation of a matching directory
tree would be pruned out.

-cd