RE: Return the contents of a file

Two things:

1) that while loop should read:

   while (<FS>) { $OP .= $_ }
[download]

Note the all-important ".=" instead of "=" (probably just a mistype on your part. :)

2) your opens should always check for error messages, and you should get faster results slurping the whole file in as one string, like so:

    sub readfile {
        my $OP;
        open FS, $_[0] or die "Can't open $_[0]: $!";
        {
            local $/ = undef;
            $OP = <FS>;
        }
        close FS or die "Can't close $_[0]: $!";
        return $OP;
    }
[download]

Comment on RE: Return the contents of a file Select or Download Code

Replies are listed 'Best First'.
RE: Return the contents of a file by turnstep (Parson) on Apr 12, 2000 at 18:02 UTC
Here's another version: `sub readfile { local $/="" unless wantarray; return open(FS, shift) ? <FS> : undef; }` [download] No 'my' variables, handles both string and array requests, and returns undef if the file could not be opened. Use it like this: `defined($slurp = &readfile($file)) or die "Could not open $file: $!\n" +; print "Scalar 'slurp' now has ", length $slurp, " characters in it\n"; defined(@slurp = &readfile($file)) or die "Could not open $file: $!\n" +; print "Array 'slurp' now has ", $#slurp, " elements in it.\n";` [download]	[reply] [d/l] [select]
RE: RE: Return the contents of a file by anders (Initiate) on May 26, 2000 at 17:41 UTC
WOW! Just loves to see this. -anders	[reply]
RE: RE: Return the contents of a file by Chris (Novice) on Apr 12, 2000 at 05:50 UTC
I REALLY do like this one. I've found that it works great for small files. Has anyone had any experiences using this technique w/ something large like a *.cvs file from a database dump? Are there any memory issues to handling a variable that large. -- I shouldn't thinks so. Hmmm...	[reply]
RE: RE: RE: Return the contents of a file by btrott (Parson) on Apr 12, 2000 at 07:18 UTC
There are memory issues in having very large variables, just as there would be, presumably, in any language. Perl variables take up a lot of space. From perlfaq3: `When it comes to time-space tradeoffs, Perl nearly always prefers to throw memory at a problem. Scalars in Perl use more memory than strings in C, arrays take more that, and hashes use even more.` [download] I mean, if you can process a file line by line, it's best to do so.	[reply] [d/l]


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