Question about Tie::File 1

[max1x]

I have read the documentation and I might be running slow today, but for some reason I can't figure out how to implement it.

I have a flat file where I need to modify records with in the file that are passed by a user. There can be a single or multiple records to modify/delete.

use CGI qw/:all/;
use CGI::Carp qw(fatalsToBrowser);
use Date::Calc qw( Delta_Days Add_Delta_Days );
print "Content-type:text/html\n\n";

@p = (param());
@recordsToDelete = param($p[0]);

open file,"+> /path/to/file" || die "Cannot open file:($!)\
n";
foreach $recordToDelete (sort @recordsToDelete) {
                ($recordNumberToDel) = split (/\s+/,$recordToDelete);
while (<file>) {
        ($recordNumber,$many,$more) = split(/\|/,$_);
                chomp ($recordNumber,$recordNumberToDel);
                s/$recordNumber/Delete/g if ($recordNumber == $recordNumberToDel);
        }
}
close file;

In case of above the file is overwritten with no data.

Alternatively.

use Tie::File;

tie @array,Tie::File,/path/to/file or die ($!\n);
foreach $recordToDelete (sort @recordsToDelete) {
                ($recordNumberToDel) = split (/\s+/,$recordToDelete);

moving forward, do I need to split the @array and then compare each to record and then modify/delete? I've tried several things, but it seems to give the same end result of a file being overwritten or empty. With @array, I'm also worried about memory consumption.

Any advice...as it seems my brain has already taken to the festivities and refuses to think straight.

 

[travs69]

You didn't really finish the second part of your example. With Tie::File you will just be manipulate the array. I don't see you doing anything with the @array.

I don't have perl on the machine I'm currently on (in training )

but something like

tie @array,Tie::File,/path/to/file or die ($!\n);
for my $stuff (@stuffiwannadelete){
@array = grep !/$stuff/, @array;
}

lots of better ways to do it I'm sure..


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[max1x]

Travis,

Enjoying your training there I see ...

I'm not sure what to do with @array, as from what I'm reading in the docs, I'll have to split the @array, the cmp to the records that are passed and then del?

Like I said, I'm having a constant brain freeze, which even caffine is not helping with...

Reading the docs again...

 

[travs69]

Can you give me an example of what will be in your file and what is being passed in from the user?

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[max1x]

The file contains data like so:

1|more|data|here
2|more|data|here
3|more|data|here

The user preforms a data based query and the records are renderd with checkboxes, which they can check to del a single or multiple record. I have given the checkbox the same value as the record number (1 2 3).

The resulting page receives these values, opens the file and can either replace the recordNumber with DEL (so I can skip that record) or completely del the entire line <-- This is where I'm having an issue.

 

[PaulTEG]

can't you just splice the offending elements of the array [-1] of course

Paul
------------------------------------
Spend an hour a week on CPAN, helps cure all known programming ailments ;-)

 

[travs69]

Not tested in any way what so ever..

tie @array, 'Tie::File', filename or die ...;

#This is just a guess
@records = param(ToDelete);

#Iterate through each rcords
for my $records (@records) {

	#Iterate through each value of the array by index
	for my $num (0..$#array) {

		#Split the values up on pipe into tmp
		my @tmp = split (/\|/, $array[$num]);

		#Compare $tmp[0] to $records
		if ($records eq $tmp[0]) {
			splice(@array,$num,1);
		}
	}
}
	

untie @array;

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[max1x]

Travis,

Exactly what I was lookin for, with one mod.

if ($records == $tmp[0])

Paul,

splice did the trick...

 

[travs69]

Yep.. sorry.. I forgot it was numbers.. and again sorry I couldn't test it better but no perl here..

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[KevinADC]

You don't need to compare anything if the checkboxes have numbers that correspond to the lines in the file:

1|more|data|here
2|more|data|here
3|more|data|here

You just use the number as the array index minus one.

------------------------------------------
- Kevin, perl coder unexceptional!

 

[travs69]

I guess we don't know his complete structure..

if it is
1|
2|
3|
4|
5|

and he delete's 3| what if another 3| never gets put in (and I'm assuming he isn't really keeping them in order)?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[KevinADC]

true, which is why I said:

You don't need to compare anything if the checkboxes have numbers that correspond to the lines in the file:

------------------------------------------
- Kevin, perl coder unexceptional!

 

[travs69]

picky picky.. you need to bold that if the first time so I see it

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[max1x]

Travis,Kevin,

The record numbers do not correspond the line numbers.