--- "Curtis, Jonathan" <[EMAIL PROTECTED]> wrote:
> This subroutine takes the user's login name ($ntlogin) and searches the flat
> file for matching entry.
>
> The flatfile contains user info, comma delimited... each user separated by
> line. The flatfile is read by line into @data, then splits each field of
> @data by comma into @cheese as it searches for the correct login name
>
> so values in cheese would look like
> $cheese[0] = jcurtis
> $cheese[1] = Jonathan Curtis
> $cheese[2] = <mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED]
> ....
>
> The loop should return a flag ($found =1) and the line number ($eindex) of
> th sub have_we_met{
my $ntlogin = shift;
die "\$ntlogin is undefined!" if ! defined $ntlogin;
my ( $found, $eindex ) = 0;
my ( $name, $email );
open DATA, "< bigdawgs.txt" or die "Cannot open bigdawgs.txt for reading: $!";
while (<DATA>)
{
my @cheese = split /,/;
if ($cheese[0] eq $ntlogin)
{
$found=1;
$eindex=$i;
( $name, $email ) = @cheese[1,2];
last;
}
$eindex++;
}
close DATA;
$eindex = undef if ! $found;
return ( $found, $eindex, $name, $email );
}e user's data...
> --
>
> sub have_we_met{
> open DATA, "bigdawgs.txt";
> @data = <DATA>;
> close DATA;
> $
> $found = 0;
>
> for ($i = 0; $i <= $#data; $i++){
> @cheese = split /,/, $data[$i];
> if ($cheese[0] eq $ntlogin) {
> $found=1;
> $eindex=$i;
> }
> }
>
> }
>
> ---
It's terribly important to ensure that you are indenting well and match curly braces
with the
proper scope. Otherwise, it's difficult to be sure which curly brace matches which
scope. In
this case, however, this does not appear to be your problem.
> The line in bold "if ($cheese[0] eq $ntlogin) {" causes error "Use of
> uninitialized value..." for each repetition of the loop.
> I know $ntlogin is initialized cause it's used all over the place...
> I know @cheese is getting info, because I can print it's contents.
Jon,
>From what you are saying, it appears that you are using $ntlogin as a global
>variable. This is
generally bad practice because it makes it more difficult to find out what part of
your code might
be changing the value of $ntdata.
When writing subroutines, it's a good practice to make them little black boxes.
Everything you
need gets passed to it and it returns everything you expect, without resorting to
globals. This
gives you fine-grained control of the functions and makes it easier to reuse them.
What follows
is a quick rewrite of your code. First, the subroutine:
01 sub have_we_met{
02 my $ntlogin = shift;
03 die "\$ntlogin is undefined!" if ! defined $ntlogin;
04 my ( $found, $eindex ) = 0;
05 my ( $name, $email );
06 open DATA, "< bigdawgs.txt" or die "Cannot open bigdawgs.txt for reading:
$!";
07
08 while (<DATA>)
09 {
10 my @cheese = split /,/;
11 if ($cheese[0] eq $ntlogin)
12 {
13 $found=1;
14 ( $name, $email ) = @cheese[1,2];
15 last;
16 }
17 $eindex++;
18 }
19 close DATA;
20 $eindex = undef if ! $found;
21 return ( $found, $eindex, $name, $email );
22 }
In line 02, we explicitly pass in $ntlogin. This has a local scope and will not
affect any other
value of $ntlogin anywhere in the script. Line 03 dies if this value is undefined.
Very useful
for error checking.
Lines 04 and 05 set up some variables that we're going to use in this sub. These
variables will
later be returned. $eindex is probably superfluous as I suspect you were using this
to find the
appropriate index in @data in order to get the name and email. If this is what you
were doing,
you don't have to return this.
Line 06 opens the file for reading and dies if the file is not found. For more
general use, you
should either pass in the file name or declare it as a constant at the top of your
code.
Lines 08 through 18 iterate over over the incoming data, looking for the $ntlogin.
I've changed
the name of the filehandle to USER_DATA to avoid potential problems with the __DATA__
token. Note
that if you have a large data file, the @data array could be quite huge. The new
subroutine
doesn't bother to read the entire file at once, thus saving memory.
Lines 11 through 16 check to see if $ntlogin matches. If so, we set $found to a true
value and
use an array slice in line 14 to set the $name and $email. Then we *last* out of the
while loop.
Since we've found what we need, there's no reason to continue.
Line 17 increments $eindex, but I suspect that you won't need this, unless the line
number is
important.
Side note: $eindex can be replaced with the special $. (dollar dot) variable. This
variable is
the current input line number of the last filehandle read. However, I didn't use it
as it seems
to make many people hyperventilate :)
Line 19: close the file.
Line 20: can probably be discarded.
Line 21: return the data. Note that all values other than $found will be undef if
nothing is
found. Heck, we could probably skip $found and $eindex and in your subsequent code,
check to see
if the subroutine returned defined values for $name and $email. If not, you know the
name wasn't
found. I think that's better, but I wanted to keep this reasonably close to what you
had.
Here's how you call the sub:
01 my ( $found, $eindex, $name, $email ) = have_we_met( $ntlogin );
02
03 if ( ! $found )
04 {
05 # error handling
06 # all values except $found will be undef
07 }
08 else
09 {
10 # it was found, proceed as normal
11 }
That should be pretty straightforward. Incidentally, here's something a little closer
to how I
would write this:
sub have_we_met
{
my ( $ntlogin, $user_data ) = @_;
die "\$ntlogin is undefined!" if ! defined $ntlogin;
my ( $name, $email );
open USER_DATA, "< $user_data" or die "Cannot open $user_data for reading: $!";
while (<USER_DATA>)
{
my @cheese = split /,/;
if ($cheese[0] eq $ntlogin)
{
( $name, $email ) = @cheese[1,2];
last;
}
}
close DATA;
return ( $name, $email );
}
my ( $name, $email ) = have_we_met( $ntlogin, $filename );
if ( ! defined $name )
{
# error handling
# all values except $found will be undef
}
else
{
# it was found, proceed as normal
}
If you have any questions, let us know.
Cheers,
Curtis "Ovid" Poe
=====
"Ovid" on http://www.perlmonks.org/
Someone asked me how to count to 10 in Perl:
push@A,$_ for reverse q.e...q.n.;for(@A){$_=unpack(q|c|,$_);@a=split//;
shift@a;shift@a if $a[$[]eq$[;$_=join q||,@a};print $_,$/for reverse @A
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