Danny Fang am Montag, 21. November 2005 13.59:
> Hi,
Hello Danny
> I'm new to PERL and would like to seek help for the task mentioned below:
>
> I'm attempting to read the contents of a file containing rows with the
> format shown below:
> version|exchange|...
> E1440000100TT|006030766|0521|...
>
> I'm interested in modifying the values at the 3rd and 26th column of 1
> particular row in this file and duplicating that row values to populate it
> to 4000 rows. There are 2123 rows in the this file currently.
>
> Below is the script which I've written in order to modify the values at
> the column mentioned.
>
> However, I'm not sure how I could rewrite the newly modified column
> values of that particular row back into the file - I want to use the
> particular row which had its columns modified to be duplicated and appended
> to the end of the current file for a specific number of time (adding more
> rows with the duplicated rows).
>
>
> version|exchange|area|...
> E1440000100TT|006030766|...
> E1440000100TT|006030766|...
>
> Could anyone help me out?
>
> Thanks
> Danny
Don't forget to check user input to the script.
> ##open file for reading
> open(INPUTFILE, $inputFile) || die "Cannot open $inputFile \n";
> @fileRecs = <INPUTFILE>;
close the file here...
perldoc -f close
> $totalRecs = scalar(@fileRecs)-1;
This will return -1 if there are no lines.
> print "Total records in $inputFile is $totalRecs \n";
> ##open file for writting output
>
> open(OUTFILE, ">$inputFile.tmp") || die "Cannot open $inputFile.tmp \n";
... and reopen it in append mode instead of above.
open (OUTFILE, '>>', $inputFile.tmp)
or die "Cannot open $inputFile.tmp: $! \n";
(note the usage of $! to get the system error).
perldoc -f open
perldoc perlvar
> $secondRow = $fileRecs[2];
> print "BEGINNING -- secondRow = $secondRow \n";
$secondRow (scalar) does not exist, but @secondRow (array) does.
You are warned if such thins occur if you put the following lines at the
beginning of every script oder module:
use strict;
use warnings;
> @secondRowRec = split("|", $secondRow);
>
> $secondRowRec[2]="AAAA";
> $secondRowRec[3]="BBBBB";
>
> print "\$secondRowRec[2] = $secondRowRec[2] and
> \$secondRowRec[3]=$secondRowRec[3] \n";
>
> print "\$secondRow is now $secondRow \n";
>
> $diffOfNewRec = 4000 - $totalRecs;
>
> print "Need to produce additional $diffOfNewRec \n";
>
> #making a backup copy
> `cp $inputFile $inputFile.tmp`;
You have this file already opened; and no error checking is done for the copy
operation.
perldoc -f system
perldoc perlop ("Quote and Quote-like Operators")
perldoc File::Copy
> ## I'm need help here !! Not sure how I could re-join the elements
> modified back into the array containing that particular row and append it
> to the end of the file ##
> print OUTFILE for ($i=0;$i<$diffOfNewRec; $i++){
> print OUTFILE "$secondRow\n";
> }
You could pack the row changements and the appending to the file in a loop:
for (1..$diffOfNewRec) {
# change the row in some way here
my $line=join '|', @secondRow; # concat values
print OUTFILE $line, "\n"; # and append it to the file
}
close OUTFILE or die $!;
perldoc perlsyn (loops)
perldoc -f join
> close OUTFILE;
hoping to help
joe
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