django-csv

Some CSV Utilities for your django projects

=========== Basic Usage

1. pip install django-csv
2. from django_csv import CSVUtilities
3. Create a new CSVUtilities instance with a single parameter, the path to a CSV file

=========== Main Methods

read_csv_into_model(model, csv_indices, delimeter=',', filter_fun=None, after_creation=None, start_row=0, dry_run=False, init_args={})

---

Create django model instances from the rows of this CSVUtilities instance's csv file. Each row of the csv will map to a new model instance unless the row doesn't pass the filter_fun test.

Arguments:

• model - the django class to create instances of
• csv_indices - a dictionary of field names mapped to the column index in the csv which holds the field value
• delimiter - the csv delimiter
• filter_fun - a callable which receives the current row in the csv as it's single argument. Return True for the row to create a new model instance and False for the row to be skipped. If not provided, will never skip rows.
• after_creation - a callable which receives two arguments, the (unsaved) model instance and the current csv row. If after_creation is provided you are responsible for calling save() to write the instance to the db.
• start_row - the row in the csv to start reading from
• dry_run - if True, no model instances will be saved, just the count of the number of model instances that would be created will be returned.
• init_args - dictionary of attributes to set for every created model instance

write_model_to_csv(model, csv_file=None, delimiter=',', header_row=False, qs=None)

---

Write django model instances to either the csv file at this CSVUtilities instance's path or the path given by csv_file if it is given.

Arguments:

• model - the django class to read instances from
• csv_file - if given, this is the path to the csv file to write. If not given, we use the path in this CSVUtilities instance.
• delimiter - the csv delimiter
• header_row - if True, the first row in the written csv file will be the model field names
• qs - a QuerySet that - if passed - will be used in place of model.objects.all() as the data source for the csv file. The models of qs should be of the same type as model for data consistency.

check_pred_against_rows(pred, delimiter=',')

---

Get a list of all csv rows that pass the given predicate

Arguments:

• pred - a callable which receives the current csv row as its single parameter and should return a truthy value
• delimiter - the csv delimiter

csv_from_excel(excel_file, csv_name)

Create a csv file from an excel file. Note: Requires xlrd package.

Arguments:

• excel_file - a File object which we'll create the csv file from
• csv_name - path to the csv file to create (shouldn't include the .csv extension)

=========== Examples

Base Class:

class DjangoClass(models.Model):
  name = models.CharField(max_length=200)
  age = models.IntegerField()

CSV File (filename: 'ppl.csv'):

1,Joe Schmo,I like cars,22
2,Bob Stein,I like turtles,24
3,Mary Jane,I like spiders,35

Basic example of reading into model:

import django_csv

csv_utils = django_csv.CSVUtilities('ppl.csv')
csv_utils.read_csv_into_model(DjangoClass, {
  'name': 1,
  'age': 3
})

Basic example of creating csv from excel file:

from django_csv import CSVUtilities

def some_view(request):
  CSVUtilities.csv_from_excel(request.FILES.get('excel_file'), 'csvs/some/csv')

Basic example of writing model instances to csv file:

from django_csv import CSVUtilities

def some_view(request):
  csv_utils = django_csv.CSVUtilities('ppl.csv')
  csv_utils.write_model_to_csv(DjangoClass)

More advanced (and admittedly convoluted) example of reading into model:

import django_csv

class Description(models.Model):
  text = models.TextField()

class DjangoClass(models.Model):
  name = models.CharField(max_length=200)
  age = models.IntegerField()
  description = models.ForeignKey(Description)
  
  @staticmethod
  def _after_create(instance, row):
    description = Description.objects.create(text = row[2])
    instance.description = description
    instance.save()
    
  @classmethod
  def create_from_csv(cls):
    csv = 'ppl.csv'
    csv_utils = django_csv.CSVUtilities(csv)
    csv_utils.read_csv_into_model(DjangoClass, {
      'name': 1,
      'age': 3
    }, after_creation=cls._after_create)