cutplace 0.8.7

validated reading of tabular files (CVS, Excel, ODS, PRN)

Cutplace is a tool and API to validate that tabular data stored in CSV, Excel, ODS and PRN files conform to a cutplace interface definition (CID).

As an example, consider the following customers.csv file that stores data about customers:

ID,surname,first_name,born,gender
3798,Miller,John,1978-11-27,male
19253,Webster Inc.,,1950-01-12,
46418,Jane,Doe,2003-06-29,female

A CID can describe such a file in an easy to read way. It consists of three sections. First, there is the general data format:

	Property	Value
D	Format	Delimited
D	Encoding	UTF-8
D	Header	1
D	Line delimiter	LF
D	Item delimiter	,

Next there are the fields stored in the data file:

	Name	Example	Empty	Length	Type	Rule
F	customer_id	3798			Integer	0…99999
F	surname	Miller		…60
F	first_name	John	X	…60
F	date_of_birth	1978-11-27			DateTime	YYYY-MM-DD
F	gender	male	X		Choice	female, male

Optionally you can describe conditions that must be met across the whole file:

	Description	Type	Rule
C	customer must be unique	IsUnique	customer_id

The CID can be stored in common spreadsheet formats, in particular Excel and ODS, for example customers_cid.ods.

Cutplace can validate that the data file conforms to the CID:

$ cutplace customers_cid.ods customers.csv

Now add a new line with a broken date_of_birth:

73921,Harris,Diana,04.08.1913,female

Cutplace rejects this file with the error message:

customers.csv (R5C4): cannot accept field ‘date_of_birth’: date must match format YYYY-MM-DD (%Y-%m-%d) but is: ‘04.08.1913’

Additionally, cutplace provides an easy to use API to read and write tabular data files using a common interface without having to deal with the intrinsic of data format specific modules. To read and validate the above example:

import cutplace
import cutplace.errors

cid_path = 'customers_cid.ods'
data_path = 'customers.csv'
try:
    for row in cutplace.rows(cid_path, data_path):
        pass  # We could also do something useful with the data in ``row`` here.
except cutplace.errors.DataError as error:
    print(error)

For more information, read the documentation at http://cutplace.readthedocs.org/ or visit the project at https://github.com/roskakori/cutplace.