Re^4: string manipulation

Last Question :-) I open file to read and should retrevie all the lines start with " SOURCE=.\" as display below:

SOURCE=.\ApplicationObject.cpp
SOURCE=.\BusinessObject.cpp
SOURCE=.\ClientObject.cpp
SOURCE=.\ComponentServer.cpp
SOURCE=.\main.cpp
SOURCE=.\posix_timer.cpp
SOURCE=.\ServiceServer.cpp
SOURCE=.\SystemObject.cpp
SOURCE=.\TestProgram.cpp
SOURCE=.\workflow.cpp
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I need to initialize variable only with the file name, so finally I should have:
$fileLst=" ApplicationObject.cpp BusinessObject.cpp ClientObject.cpp ComponentServer.cpp" My current code is:

foreach my $line (<MAKFILE>) {
         chomp $line;
        if ($line =~ m/SOURCE=\.\\(.*)$/i) {
            push @fileLst, $1;
        }
    } 
    close MAKFILE;
    
    $fileLst = join " ", @fileLst;
    return $fileLst;
[download]

The final result includes garbage: "workflow.cppcppppppp".
Please advice. Thanks.

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Re^5: string manipulation by blazar (Canon) on May 18, 2008 at 15:31 UTC
`foreach my $line (<MAKFILE>) {` [download] I personally believe you should know that almost always in Perl (5) the Right™ way to iterate over the lines of a file is a `while` loop. You should also be using lexical filehandles. `if ($line =~ m/SOURCE=\.\\(.)$/i) {` [download] I generally chomp too, but incidentally `$` matches right before `\n` too; you may also push the return value of the match operator. `$fileLst = join " ", @fileLst;` [download] Perhaps you prefer to be explicit, and I'm sure many people would say that you're right, but there's a very convenient shortcut for `join " ", @fileLst`, which is `"@fileLst"`; also, I see no reason to create an intermediate temporary variable just to return it. All in all, I will give you an example subroutine which will accept a filename and give you your expected output: sub domkfile { my ($fname, @flist)=shift; open my $fh, '<', $fname or die "Can't open `$fname': $!\n"; push @flist, /SOURCE=\.\\(.)$/i while <$fh>; "@flist"; } [download] If slurping the whole file at once is not a problem, and indeed it should not be in this case, you may avoid the use of the `@flist` array with a map: sub domkfile { my $fname=shift; open my $fh, '<', $fname or die "Can't open `$fname': $!\n"; join ' ' => map /SOURCE=\.\\(.)$/i, <$fh>; } [download] `--` If you can't understand the incipit, then please check the IPB Campaign*.	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^5: string manipulation
by blazar (Canon) on May 18, 2008 at 15:31 UTC

foreach my $line (<MAKFILE>) {
[download]

I personally believe you should know that almost always in Perl (5) the Right™ way to iterate over the lines of a file is a while loop. You should also be using lexical filehandles.

if ($line =~ m/SOURCE=\.\\(.*)$/i) {
[download]

I generally chomp too, but incidentally $ matches right before \n too; you may also push the return value of the match operator.

$fileLst = join " ", @fileLst;
[download]

Perhaps you prefer to be explicit, and I'm sure many people would say that you're right, but there's a very convenient shortcut for join " ", @fileLst, which is "@fileLst"; also, I see no reason to create an intermediate temporary variable just to return it.

All in all, I will give you an example subroutine which will accept a filename and give you your expected output:

sub domkfile {
    my ($fname, @flist)=shift;
    open my $fh, '<', $fname or die "Can't open `$fname': $!\n";
    push @flist, /SOURCE=\.\\(.*)$/i while <$fh>;
    "@flist";
}
[download]

If slurping the whole file at once is not a problem, and indeed it should not be in this case, you may avoid the use of the @flist array with a map:

sub domkfile {
    my $fname=shift;
    open my $fh, '<', $fname or die "Can't open `$fname': $!\n";
    join ' ' => map /SOURCE=\.\\(.*)$/i, <$fh>;
}
[download]

--
If you can't understand the incipit, then please check the IPB Campaign.

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