For your first question, instead of:
$batch = MARC::Batch->new(‘USMARC’,<STDIN>);
use:
$batch = MARC::Batch->new(‘USMARC’,STDIN);
For your second, the error is likely caused when a field you're using
as_string() on doesn't exist in the record.
So, you could do something like the following:
$field = $record->field('008');
$field or do { # check for
existence of field
print "no 008 field for record\n"; # no field
next; # skip the field
(or whatever)
};
$field_008 = $field->as_string();
Hope this helps
-Tim
Timothy Prettyman
LIT/Library Systems
University of Michigan
On Thu, May 29, 2014 at 12:08 PM, John E Guillory <[email protected]> wrote:
> Hello,
>
> Two questions please:
>
>
>
> 1. I’ve written a script that opens a marc file for reading using
> this syntax:
>
>
>
> $file = $ARGV[0];
>
> $batch = MARC::Batch->new('USMARC',$file);
>
>
>
> It then loops thru the records using this syntax:
>
> while ( $record = $batch->next()) {
>
> …..check position 6, 7 of leader and position 23 of 008 and make
> some changes
>
> }
>
>
>
> This works great. However, instead of accessing the file this way, I want
> to pipe the output of a previously run marc dump command directly into this
> script via the pipe.
>
> I understand that this can be done using this syntax: while ($line
> =<STDIN>){ …}, but I don’t understand how to use that STDIN with
> “MARC::Batch->new(‘USMARC’,$file);” This does not work: $batch =
> MARC::Batch->new(‘USMARC’,<STDIN>);
>
>
>
> 2. My current script successfully reads and processes a marc file of
> over 5 gigs!....but exits entirely on record 160,585 with the error from
> MARC::Batch, “Can't call method "as_string" on an undefined value at ./
> marc_batch.pl”. Documentation on using MARC::Batch says that to tell it
> to continue processing even when errors are encountered one should use
> strict_off(), then print/report warnings at the bottom of the script. I
> don’t think my particular error is being handled by the strict_off()
> setting. Doesn’t anybody know what causes/how to fix “Can’t call method
> as_string?” error? Full script below—it’s pretty short, thanks to
> MARC::Batch.
>
>
>
> Thanks for ensights!
>
>
>
>
>
> use MARC::Batch;
>
>
>
> $file = $ARGV[0];
>
> chomp($file);
>
>
>
> $batch = MARC::Batch->new('USMARC',$file);
>
> $batch->strict_off(); # otherwise script exits when encounters errors
>
>
>
> open(OUT,'>new_marc');
>
>
>
> while ( $record = $batch->next()) {
>
> $leader = $record->leader();
>
> $leader_pos_6 = substr($leader,6,1);
>
> $leader_pos_7 = substr($leader,7,1);
>
>
>
> $field = $record->field('008');
>
> $field_008 = $field->as_string();
>
> $field_008_position_23 = substr($field_008,23,1);
>
>
>
> if ( ($leader_pos_6 eq "a") && ($leader_pos_7 eq "m") &&
> ($field_008_position_23 eq "o") || ($field_008_position_23 eq "s") ) {
>
>
>
> $control_num = $record->field('001');
>
> $control_num = $control_num->as_string();
>
>
>
> print "008 position 23: $field_008_position_23 \n";
>
> print "OLD leader: $leader \n";
>
> $old_leader = $leader;
>
> substr($leader,6,1) = 'm';
>
> print "NEW leader: $leader \n";
>
>
>
> print OUT $record->as_usmarc();
>
> print "$control_num|$old_leader|$leader|$field_008\n";
>
>
>
> } else { # not a match so just print this one unchanged…
>
> print OUT $record->as_usmarc();
>
> }
>
>
>
> }
>
>
>
> # handles errors:
>
> if (@warnings = $batch->warnings()) {
>
> print "\n Warnings detected: \n", @warnings;
>
> }
>
>
>
> close(OUT);
>
> close(LOG);
>
>
>
>
>
>
>
> John Guillory
>
> Louisiana Library Network
>
> 225.578.3758
>
>
>
