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File writer/parser for fixed-width and character-separated files

Project description

The gocept.recordserialize distribution

File writer/parser for fixed-width and character-separated files.

This package is compatible with Python version 2.7.

Fixed-width format

Define the format by listing all fields, in order. Each field has the following settings:

name:Name of the field (required)
width:Width of the field in characters (required)
fill character:default: Space
alignment:default: align LEFT (that is, pad on the right side)

For example:

>>> from gocept.recordserialize import FixedWidthRecord
>>> class FixedExample(FixedWidthRecord):
...
...    encoding = 'utf-8'
...    lineterminator = '\r\n'
...
...    fields = [
...        ('one', 3, ' ', FixedWidthRecord.LEFT),
...        ('two', 7, '0', FixedWidthRecord.RIGHT),
...    ]

Writing

>>> r = FixedExample()
>>> r['one'] = 'foo'
>>> r['two'] = '12'
>>> str(r)
'foo0000012\r\n'

Reading

>>> r = FixedExample.parse('bar0000034\r\n')
>>> r['one']
u'bar'
>>> r['two']
u'34'

Also available: parse_file which takes a file-like object.

Character-separated format

Define the format by declaring attributes on the class. Each field has the following settings:

position:position of the field
default:default value to write if none is given
maximum length:truncate field to this length

Note that you do not have to declare all fields, any positions not declared are filled with empty columns. For this reason, you always have to give the total number of fields in the fields attribute:

>>> from gocept.recordserialize import SeparatedRecord
>>> class PipeExample(SeparatedRecord):
...
...    fields = 5
...    encoding = 'utf-8'
...    separator = '|'
...    lineterminator = '\r\n'
...
...    first = 1
...    default = 2, 'qux'
...    maxlen = 3, 3
...    maxlen_default = 4, 5, 'asdfg'

Writing

>>> r = PipeExample()
>>> r['first'] = 'some text'
>>> r['maxlen'] = '12345'
>>> str(r)
'some text|qux|123|asdfg|\r\n'

Reading

>>> r = PipeExample.parse('some text|qux|123|asdfg|\r\n')
>>> r['first']
u'some text'
>>> r['default']
u'qux'
>>> r['maxlen']
u'123'
>>> r['maxlen_default']
u'asdfg'

Also available: parse_file which takes a file-like object.

Escaping

For subclassing, SeparatedRecord provides classmethods escape and unescape that each value is passed through on write/read. An example that makes use of this is gocept.recordserialize.CSVRecord which escapes quotes:

>>> from gocept.recordserialize import CSVRecord
>>> class CSVExample(CSVRecord):
...
...     fields = 1
...     one = 1

>>> r = CSVExample()
>>> r['one'] = 'my "quoted" string'
>>> str(r)
'"my \'quoted\' string"\r\n'

Change log for gocept.recordserialize

1.0 (2017-12-06)

  • Add support for setuptools >= 32.
  • Drop support for Python 2.6.

0.3 (2016-02-29)

  • Escape unicode characters on errors.

0.2 (2013-11-26)

  • Fixed dependency on setuptools.

0.1 (2012-09-19)

initial release

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