====== pymarc ======

<note>
Atención: existe otro proyecto similar, [[http://sourceforge.net/projects/pymarc/|PyMARC en SourceForge]], by mstetson. Incluye ''MarcBreaker.py'' y ''MarcMaker.py''.
</note>

pymarc 2.0 / read, write and modify MARC bibliographic data

Web: http://pypi.python.org/pypi/pymarc/2.0

Code: http://fruct.us/bzr/pymarc/


**PACKAGE CONTENTS**

  * constants
  * exceptions
  * field
  * marc8
  * marc8_mapping
  * marcxml
  * reader
  * record
  * writer



===== record =====

  class Record(object):
    A class for representing a MARC record. Each Record object is made up of
    multiple Field objects. You'll probably want to look at the docs for Field
    to see how to fully use a Record object.
    
    Basic usage:
    
        field = Field(
            tag = '245', 
            indicators = ['0','1'],
            subfields = [
                'a', 'The pragmatic programmer : ',
                'b', 'from journeyman to master /', 
                'c', 'Andrew Hunt, David Thomas.',
            ])
    
        record.add_field(field)
    
    Or creating a record from a chunk of MARC in transmission format:
    
        record = Record(data=chunk)
    
    Or getting a record as serialized MARC21.
    
        raw = record.as_marc21()
    
    You'll normally want to use a MARCReader object to iterate through 
    MARC records in a file.  


==== Methods ====

    def __init__(self, data=''):
      Si len(data) > 0 llama a self.decode_marc(data)

    def __str__(self):
        In a string context a Record object will return a prettified version
        of the record in MARCMaker format. See the docstring for Field.__str__
        for more information.

    def __getitem__(self, tag):
        Allows a shorthand lookup by tag:
        
            record['245']

    def __iter__(self):
       Usado para iterar sobre los campos; ver next()

    def next(self):
       Usado para iterar sobre los campos

    def add_field(self, *fields):
        add_field() will add pymarc.Field objects to a Record object.
        Optionally you can pass in multiple fields.

    def get_fields(self, *args):
        When passed a tag ('245'), get_fields() will return a list of all the 
        fields in a record with a given tag. 
        
            title = record.get_fields('245')
        
        If no fields with the specified 
        tag are found then an empty list is returned. If you are interested
        in more than one tag you can pass in a list:
        
            subjects = record.get_fields('600', '610', '650') 
        
        If no tag is passed in to fields() a list of all the fields will be 
        returned.

    def decode_marc(self, marc):
        decode_marc() accepts a MARC record in transmission format as a
        a string argument, and will populate the object based on the data
        found. The Record constructor actually uses decode_marc() behind
        the scenes when you pass in a chunk of MARC data to it.

    def as_marc21(self):
        returns the record serialized as MARC21

Estos métodos devuelven campos específicos:

    def title(self):
    def isbn(self):
    def author(self):
    ...


===== field =====

  class Field(object):
    Field() pass in the field tag, indicators and subfields for the tag.
    
        field = Field(
            tag = '245',
            indicators = ['0','1'],
            subfields = [                               NOTE: positions 0, 2, 4, ... are codes; 1, 3, 5, ... are values
                'a', 'The pragmatic programmer : ',
                'b', 'from journeyman to master /', 
                'c', 'Andrew Hunt, David Thomas.',
            ]
    
    If you want to create a control field, don't pass in the indicators
    and use a data parameter rather than a subfields parameter:
    
        field = Field(tag='001', data='fol05731351')


==== Methods ====


    def __init__(self, tag, indicators=None, subfields=None, data=''):
      data se usa sólo para campos de control (tag < 010)

    def __iter__(self):
      usado para iterar sobre los subcampos (ver next())
      Devuelve: self

    def __str__(self):
        A Field object in a string context will return the tag, indicators
        and subfield as a string. This follows MARCMaker format; see [1]
        and [2] for further reference. Special character mnemonic strings
        have yet to be implemented (see [3]), so be forewarned. Note also
        for complete MARCMaker compatibility, you will need to change your
        newlines to DOS format ('\r\n').
        
        [1] http://www.loc.gov/marc/makrbrkr.html#mechanics
        [2] http://search.cpan.org/~eijabb/MARC-File-MARCMaker/
        [3] http://www.loc.gov/marc/mnemonics.html
        
        Devuelve: string

    def __getitem__(self, subfield):
        Retrieve the first subfield with a given subfield code in a field:
        
            field['a']
        
        Handy for quick lookups.

    def next(self):
      usado para iterar sobre los subcampos

    def value(self):
        Returns the field as a string without tag, indicators, and 
        subfield indicators.

    def get_subfields(self, *codes):
        get_subfields() accepts one or more subfield codes and returns
        a list of subfield values.  The order of the subfield values
        in the list will be the order that they appear in the field.
        
            print field.get_subfields('a')
            print field.get_subfields('a', 'b', 'z')
        
        Devuelve: None o lista de valores, e.g. ['Pérez, Juan,', '1954-']

    def add_subfield(self, code, value):
        Adds a subfield code/value pair to the field.
        
            field.add_subfield('u', 'http://www.loc.gov')
        
        Devuelve: nada

    def is_control_field(self):
        returns true or false if the field is considered a control field.
        Control fields lack indicators and subfields.
        
        Devuelve: boolean

    def as_marc21(self):
        used during conversion of a field to raw marc
        
        Devuelve: string

    def format_field(self):
        Returns the field as a string without tag, indicators, and
        subfield indicators. Like pymarc.Field.value(), but prettier
        (adds spaces, formats subject headings).
        
        Devuelve: string

    def is_subject_field(self):
        Returns True or False if the field is considered a subject
        field.  Used by format_field.
        
        Devuelve: boolean


{{tag>python marc}}