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Tools for working with pandas <http://pandas.pydata.org>_ in your Django
projects
Christopher Clarke <https://github.com/chrisdev>_Bertrand Bordage <https://github.com/BertrandBordage>_Guillaume Thomas <https://github.com/gtnx>_Parbhat Puri <https://parbhatpuri.com/>_Fredrik Burman (coachHIPPO) <https://www.coachhippo.com>_Safe Hammad <http://safehammad.com>_Jeff Sternber <https://www.linkedin.com/in/jeffsternberg>_@MiddleFork <https://github.com/MiddleFork>_Daniel Andrlik <https://github.com/andrlik>_Kevin Abbot <https://github.com/kgabbott>_Yousuf Jawwad <https://github.com/ysfjwd>_@henhuy <https://github.com/henhuy>_Hélio Meira Lins <https://github.com/meiralins>_@utpyngo <https://github.com/utpyngo>_Anthony Monthe <https://github.com/ZuluPro>_Vincent Toupet <https://github.com/vtoupet>_Anton Ian Sipos <https://github.com/aisipos>_Thomas Grainger <https://github.com/graingert/>_Ryan Smith <https://github.com/bixbyr/>_This is release facilitates running of test with Python 3.10 and automates
the publishing of the package to PYPI as per PR #146_
(again much thanks @graingert). As usual we have attempted support legacy
versions of Python/Django/Pandas and this sometimes results in deperation errors
being displayed in when test are run. To avoid use python -Werror runtests.py
.. _#146: https://github.com/chrisdev/django-pandas/pull/146
django-pandas supports Django (>=1.4.5) or later
and requires django-model-utils (>= 1.4.0) and Pandas_ (>= 0.12.0).
Note because of problems with the requires directive of setuptools
you probably need to install numpy in your virtualenv before you install
this package or if you want to run the test suite ::
pip install numpy
pip install -e .[test]
python runtests.pySome pandas functionality requires parts of the Scipy stack.
You may wish to consult http://www.scipy.org/install.html
for more information on installing the Scipy stack.
You need to install your preferred version of Django. as that Django 2 does not support Python 2.
.. _Django: http://djangoproject.com/ .. _django-model-utils: http://pypi.python.org/pypi/django-model-utils .. _Pandas: http://pandas.pydata.org
Please file bugs and send pull requests to the GitHub repository and issue tracker.
.. _GitHub repository: https://github.com/chrisdev/django-pandas/ .. _issue tracker: https://github.com/chrisdev/django-pandas/issues
Start by creating a new virtualenv for your project ::
mkvirtualenv myprojectNext install numpy and pandas and optionally scipy ::
pip install numpy
pip install pandasYou may want to consult the scipy documentation_ for more information
on installing the Scipy stack.
.. _scipy documentation: http://www.scipy.org/install.html
Finally, install django-pandas using pip::
pip install django-pandasor install the development version from github ::
pip install https://github.com/chrisdev/django-pandas/tarball/masterThe django-pandas.io module provides some convenience methods to
facilitate the creation of DataFrames from Django QuerySets.
read_frame ^^^^^^^^^^^
Parameters
- qs: A Django QuerySet.
- fieldnames: A list of model field names to use in creating the ``DataFrame``.
You can span a relationship in the usual Django way
by using double underscores to specify a related field
in another model
- index_col: Use specify the field name to use for the ``DataFrame`` index.
If the index
field is not in the field list it will be appended
- coerce_float : Boolean, defaults to True
Attempt to convert values to non-string,
non-numeric objects (like decimal.Decimal)
to floating point.
- verbose: If this is ``True`` then populate the DataFrame with the
human readable versions of any foreign key or choice fields
else use the actual values set in the model.
- column_names: If not None, use to override the column names in the
DateFrameExamples ^^^^^^^^^ Assume that this is your model::
class MyModel(models.Model):
full_name = models.CharField(max_length=25)
age = models.IntegerField()
department = models.CharField(max_length=3)
wage = models.FloatField()First create a query set::
from django_pandas.io import read_frame
qs = MyModel.objects.all()To create a dataframe using all the fields in the underlying model ::
df = read_frame(qs)The df will contain human readable column values for foreign key and choice
fields. The DataFrame will include all the fields in the underlying
model including the primary key.
To create a DataFrame using specified field names::
df = read_frame(qs, fieldnames=['age', 'wage', 'full_name'])To set full_name as the DataFrame index ::
qs.to_dataframe(['age', 'wage'], index_col='full_name'])You can use filters and excludes ::
qs.filter(age__gt=20, department='IT').to_dataframe(index_col='full_name')django-pandas provides a custom manager to use with models that
you want to render as Pandas Dataframes. The DataFrameManager
manager provides the to_dataframe method that returns
your models queryset as a Pandas DataFrame. To use the DataFrameManager, first
override the default manager (objects) in your model's definition
as shown in the example below ::
#models.py
from django_pandas.managers import DataFrameManager
class MyModel(models.Model):
full_name = models.CharField(max_length=25)
age = models.IntegerField()
department = models.CharField(max_length=3)
wage = models.FloatField()
objects = DataFrameManager()This will give you access to the following QuerySet methods:
- ``to_dataframe``
- ``to_timeseries``
- ``to_pivot_table``to_dataframe ^^^^^^^^^^^^^
Returns a DataFrame from the QuerySet
Parameters
- fieldnames: The model field names to utilise in creating the frame.
to span a relationship, use the field name of related
fields across models, separated by double underscores,
- index: specify the field to use for the index. If the index
field is not in the field list it will be appended
- coerce_float: Attempt to convert the numeric non-string data
like object, decimal etc. to float if possible
- verbose: If this is ``True`` then populate the DataFrame with the
human readable versions of any foreign key or choice fields
else use the actual value set in the model.Examples ^^^^^^^^^
Create a dataframe using all the fields in your model as follows ::
qs = MyModel.objects.all()
df = qs.to_dataframe()This will include your primary key. To create a DataFrame using specified field names::
df = qs.to_dataframe(fieldnames=['age', 'department', 'wage'])To set full_name as the index ::
qs.to_dataframe(['age', 'department', 'wage'], index='full_name'])You can use filters and excludes ::
qs.filter(age__gt=20, department='IT').to_dataframe(index='full_name')A convenience method for creating a time series i.e the DataFrame index is instance of a DateTime or PeriodIndex
Parameters
- fieldnames: The model field names to utilise in creating the frame.
to span a relationship, just use the field name of related
fields across models, separated by double underscores,
- index: specify the field to use for the index. If the index
field is not in the field list it will be appended. This
is mandatory.
- storage: Specify if the queryset uses the `wide` or `long` format
for data.
- pivot_columns: Required once the you specify `long` format
storage. This could either be a list or string identifying
the field name or combination of field. If the pivot_column
is a single column then the unique values in this column become
a new columns in the DataFrame
If the pivot column is a list the values in these columns are
concatenated (using the '-' as a separator)
and these values are used for the new timeseries columns
- values: Also required if you utilize the `long` storage the
values column name is use for populating new frame values
- freq: the offset string or object representing a target conversion
- rs_kwargs: Arguments based on pandas.DataFrame.resample
- verbose: If this is ``True`` then populate the DataFrame with the
human readable versions of any foreign key or choice fields
else use the actual value set in the model.Examples ^^^^^^^^^
Using a long storage format ::
#models.py
class LongTimeSeries(models.Model):
date_ix = models.DateTimeField()
series_name = models.CharField(max_length=100)
value = models.FloatField()
objects = DataFrameManager()Some sample data:::
======== ===== =====
date_ix series_name value
======== ===== ======
2010-01-01 gdp 204699
2010-01-01 inflation 2.0
2010-01-01 wages 100.7
2010-02-01 gdp 204704
2010-02-01 inflation 2.4
2010-03-01 wages 100.4
2010-02-01 gdp 205966
2010-02-01 inflation 2.5
2010-03-01 wages 100.5
========== ========== ======Create a QuerySet ::
qs = LongTimeSeries.objects.filter(date_ix__year__gte=2010)Create a timeseries dataframe ::
df = qs.to_timeseries(index='date_ix',
pivot_columns='series_name',
values='value',
storage='long')
df.head()
date_ix gdp inflation wages
2010-01-01 204966 2.0 100.7
2010-02-01 204704 2.4 100.4
2010-03-01 205966 2.5 100.5Using a wide storage format ::
class WideTimeSeries(models.Model):
date_ix = models.DateTimeField()
col1 = models.FloatField()
col2 = models.FloatField()
col3 = models.FloatField()
col4 = models.FloatField()
objects = DataFrameManager()
qs = WideTimeSeries.objects.all()
rs_kwargs = {'how': 'sum', 'kind': 'period'}
df = qs.to_timeseries(index='date_ix', pivot_columns='series_name',
values='value', storage='long',
freq='M', rs_kwargs=rs_kwargs)A convenience method for creating a pivot table from a QuerySet
Parameters
Example ::
# models.py
class PivotData(models.Model):
row_col_a = models.CharField(max_length=15)
row_col_b = models.CharField(max_length=15)
row_col_c = models.CharField(max_length=15)
value_col_d = models.FloatField()
value_col_e = models.FloatField()
value_col_f = models.FloatField()
objects = DataFrameManager()Usage ::
rows = ['row_col_a', 'row_col_b']
cols = ['row_col_c']
pt = qs.to_pivot_table(values='value_col_d', rows=rows, cols=cols).. end-here