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Python types for reading and writing fixed text-oriented data records
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Encode and Decode Textual Data into Rich Python Data Structures

stypes is a text parsing, conversion and formatting library written to efficiently handle large fixed-width text record data files. Convert text streams into dictionaries, lists, tuples, named tuples, ordered dictionaries and more using text layout specifications. Nested data structures and repeating elements are also supported.

One of the main design goals of the library was to handle legacy text-based record data that is commonly found in COBOL system. Of course, the library can be used to handle any fixed layout textual data.

A simple example of turning some text into a Named Tuple:

from decimal import Decimal
from stypes import NamedTuple, Integer, Numeric
spec = NamedTuple([
    ('name', 10),
    ('age', Integer(3)),
    ('weight', Numeric('999V99'))])
text = "Johnson    2109750"
rec = spec.unpack(text)
assert == 'Johnson'
assert rec.age == 21
assert rec.weight == Decimal("97.5")

And a more interesting example using nested data structures of a list of records and actually updating a record.

from stypes import Array, Dict, Integer, Numeric
item = Dict([('line_no', Integer(2)),
    ('item_no', Integer(5)),
    ('total', Numeric("999.99"))])
invoice = Dict([
    ('invoice_no', Integer(4)),
    ('total', Numeric("999.99")),
    ('items', Array(3, item))])
text = "0001200.450100004002.000200006198.50"
rec = invoice.unpack(inv)
# rec is now
  {'invoice_no': 1,
   'items': [{'item_no': 4, 'line_no': 1, 'total': Decimal('2.00')},
         {'item_no': 6, 'line_no': 2, 'total': Decimal('198.50')},
         {'item_no': None, 'line_no': None, 'total': None}],
   'total': Decimal('200.45')}

# Set the last invoice item
rec['items'][-1] = {
    'line_no': 3,
    'item_no': 10,
    'total': Decimal("20")}

# Update the invoice total
rec['total'] = sum(i['total'] for i in rec['items'])
print rec.pack()
# '0001220.500100004002.000200006198.500300010020.00'

See the included file for more examples.

You can install stypes using pip

pip install stypes

or download from PyPI at

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