CSVs are awesome, yet they're pretty dumb. Let's get them smarter!
smartcsv is a python utility to read and parse CSVs based on model definitions. Instead of just parsing the CSV into lists (like the builtin csv module) it adds the ability to specify models with attributes names. On top of that it adds nice features like validation, custom parsing, failure control and nice error messages.
pip install smartcsv
To see an entire set of usages check the test package (99% coverage).
The basic is to define a spec for the columns of your csv. Assuming the following CSV file:
title,category,subcategory,currency,price,url,image_url
iPhone 5c blue,Phones,Smartphones,USD,399,http://apple.com/iphone,http://apple.com/iphone.jpg
iPad mini,Tablets,Apple,USD,699,http://apple.com/iphone,http://apple.com/iphone.jpg
First you need to define the spec for your columns. This is an example (the one used in tests):
COLUMNS_1 = [
{'name': 'title', 'required': True},
{'name': 'category', 'required': True},
{'name': 'subcategory', 'required': False},
{
'name': 'currency',
'required': True,
'choices': CURRENCIES
},
{
'name': 'price',
'required': True,
'validator': is_number
},
{
'name': 'url',
'required': True,
'validator': lambda c: c.startswith('http')
},
{
'name': 'image_url',
'required': False,
'validator': lambda c: c.startswith('http')
},
]You can then use smartcsv to parse the CSV:
import smartcsv
with open('my-csv.csv', 'r') as f:
reader = smartcsv.reader(f, columns=COLUMNS_1)
for obj in reader:
print(obj['title'])smartcsv.reader uses the builtin csv module and accepts a dialect to use.
Assuming a CSV with the an error in the second row.
reader = smartcsv.reader(f, columns=COLUMNS_1, fail_fast=False)
for obj in reader:
print obj['title']
row = reader.errors['rows'][1] # Second row has index = 1. Errors are 0-indexed.
print(error_row['row']) # Print original row data
print(error_row['errors'].keys()) # currency (the currency column)
print(error_row['errors']['currency']) # Invalid currency... (nice error explanation)You can also specify a max_failures parameter. It will count failures and will raise an exception when that threshold is exceeded.
Strip white spaces
By default the strip_white_spaces option is set to True. Example:
sample.csv
title,price
Some Product , 55.5
row['title'] will be "Some Product" and row['price'] will be "55.5" (spaces stripped)
Skip lines
sample.csv
GENERATED BY AWESOME SCRIPT
2014-08-12
title,price
Some Product,55.5
The first 3 lines don't contain any valuable data so we'll skip them.
reader = smartcsv.reader(f, columns=COLUMNS_1, fail_fast=False, skip_lines=3)
for obj in reader:
print obj['title']Fork, code, watch your tests pass, submit PR. To test:
$ python setup.py test # Run tests in your venv
$ tox # Make sure it passes in all versions.