Richard,
Do you want to generate an .mrk file as output? The following code will
generate a .mrk file with an output record for every input record, but the
output records will only have 035 fields.
from pymarc import Record, MARCReader
with open(r'C:\Users\RickRigby\Desktop\RichardLGuinninterests\foo.mrc',
'rb') as marc_input:
with
open(r'C:\Users\RickRigby\Desktop\RichardLGuinninterests\bah.mrk','w') as
text_output:
for input_record in MARCReader(marc_input):
the_fields = input_record.get_fields('035')
new_record = Record()
new_record.add_field(*the_fields)
text_output.write(str(new_record))
This will output just a leader for any input records that don't have 035s.
If you wanted to skip those records you'd have to check the_fields against
null.
If this *isn't* the output format you wanted, perhaps you can give us an
example of what you are looking for?
Graeme Williams
Las Vegas, NV
On Thu, May 14, 2020 at 1:41 PM Ned Stewart <[log in to unmask]> wrote:
> Hi Richard,
>
> I'm with Mark in thinking that you don't need the MARCWriter for the
> second part.
>
> Also, I think I'd do another for loop, like in the first part, after
> opening the file:
>
> for fld in ARN:
> ARNfile.write(fld + '\n')
>
>
> And then close the file. Pretty sure you need to add your own line feed,
> thus the fld + '\n'
>
> Hope this helps a little as well,
>
> Ned
>
> -----Original Message-----
> From: Code for Libraries <[log in to unmask]> On Behalf Of Mark A.
> Matienzo
> Sent: Thursday, May 14, 2020 3:47 PM
> To: [log in to unmask]
> Subject: Re: [CODE4LIB] PyMARC question
>
> Hi Richard,
>
> It seems like your code in the first part might be working as expected -
> does it print the 035 fields as you expect?
>
> PyMARC's `get_fields()` function will return either a Python list of Field
> objects, or an empty list (`[]`) if there are no matching fields for the
> given tag. This leads to the case where `ARNfile.write(ARN)` won't work,
> because you have to cast the Python list to a string first.
>
> Also, it seems like you probably don't need to import the `MARCWriter`
> class if I'm understanding your needs - that is for writing files of MARC
> records themselves.
>
> Hope that helps,
> Mark
>
> --
> Mark A. Matienzo
> Unceded Ohlone Territory / San Mateo, California
>
> https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmatienzo.org%2F&data=02%7C01%7Cnstewart%40FLVC.ORG%7C52794ea2336a4ae6cdfb08d7f83fb188%7C60ebd441a2f94841802f22bf1380b4ae%7C0%7C0%7C637250824752827635&sdata=3d%2BvJIL7SpxlyM7dNWvJJPFv9l%2F8G%2BPDSYBixjAS3FA%3D&reserved=0
>
>
> On Thu, May 14, 2020 at 12:22 PM Richard Guinn <[log in to unmask]>
> wrote:
>
> > Hello
> >
> >
> > Apologies for a very basic question - but I am running into a wall
> > with some code.
> >
> >
> > I am very new to Python and PyMARC.
> >
> >
> > I am trying to use PyMARC to pull a list of 035's from a list of
> > MARC21 records. I want to have the list of 035's to output to a text
> file.
> >
> >
> > My code thus far:
> >
> >
> > # List all OCLC numbers in the file
> >
> > import pymarc
> > from pymarc import MARCReader
> >
> > with
> > open(r'C:\Users\RickRigby\Desktop\RichardLGuinninterests\metadataMARC.
> > mrc','rb')
> > as fh:
> > reader = MARCReader(fh)
> > for record in reader:
> > print(record['035'])
> >
> > from pymarc import MARCWriter
> >
> > ARN = record.get_fields('035')
> > ARNfile =
> > open(r'C:\Users\RickRigby\Desktop\RichardLGuinninterests\metadata.mrk'
> > ,'w')
> > ARNfile.write(str(ARN))
> > ARNfile.close()?
> >
> > it creates a text file but with nothing in the file.
> >
> > How can I get this to work?
> >
> > Also - I would like a list in the text file but when I use just
> > ARNfile.write(ARN)
> > I get a TypeError: TypeError: write() argument must be str, not list
> >
> > I'm not sure if there's a way to get around that...
> >
> > Thank you very much for any help!
> > Richard
> >
>
