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Using BigQuery with Pandas
~~~~~~~~~~~~~~~~~~~~~~~~~~
Retrieve BigQuery data as a Pandas DataFrame
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
As of version 0.29.0, you can use the
:func:`~google.cloud.bigquery.table.RowIterator.to_dataframe` function to
retrieve query results or table rows as a :class:`pandas.DataFrame`.
First, ensure that the :mod:`pandas` library is installed by running:
.. code-block:: bash
pip install --upgrade pandas
Alternatively, you can install the BigQuery Python client library with
:mod:`pandas` by running:
.. code-block:: bash
pip install --upgrade 'google-cloud-bigquery[pandas]'
To retrieve query results as a :class:`pandas.DataFrame`:
.. literalinclude:: ../snippets.py
:language: python
:dedent: 4
:start-after: [START bigquery_query_results_dataframe]
:end-before: [END bigquery_query_results_dataframe]
To retrieve table rows as a :class:`pandas.DataFrame`:
.. literalinclude:: ../snippets.py
:language: python
:dedent: 4
:start-after: [START bigquery_list_rows_dataframe]
:end-before: [END bigquery_list_rows_dataframe]
The following data types are used when creating a pandas DataFrame.
.. list-table:: Pandas Data Type Mapping
:header-rows: 1
* - BigQuery
- pandas
- Notes
* - BOOL
- boolean
-
* - DATETIME
- datetime64[ns], object
- The object dtype is used when there are values not representable in a
pandas nanosecond-precision timestamp.
* - DATE
- dbdate, object
- The object dtype is used when there are values not representable in a
pandas nanosecond-precision timestamp.
Requires the ``db-dtypes`` package. See the `db-dtypes usage guide
<https://googleapis.dev/python/db-dtypes/latest/usage.html>`_
* - FLOAT64
- float64
-
* - INT64
- Int64
-
* - TIME
- dbtime
- Requires the ``db-dtypes`` package. See the `db-dtypes usage guide
<https://googleapis.dev/python/db-dtypes/latest/usage.html>`_
Retrieve BigQuery GEOGRAPHY data as a GeoPandas GeoDataFrame
------------------------------------------------------------
`GeoPandas <https://geopandas.org/>`_ adds geospatial analytics
capabilities to Pandas. To retrieve query results containing
GEOGRAPHY data as a :class:`geopandas.GeoDataFrame`:
.. literalinclude:: ../samples/geography/to_geodataframe.py
:language: python
:dedent: 4
:start-after: [START bigquery_query_results_geodataframe]
:end-before: [END bigquery_query_results_geodataframe]
Load a Pandas DataFrame to a BigQuery Table
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
As of version 1.3.0, you can use the
:func:`~google.cloud.bigquery.client.Client.load_table_from_dataframe` function
to load data from a :class:`pandas.DataFrame` to a
:class:`~google.cloud.bigquery.table.Table`. To use this function, in addition
to :mod:`pandas`, you will need to install the :mod:`pyarrow` library. You can
install the BigQuery Python client library with :mod:`pandas` and
:mod:`pyarrow` by running:
.. code-block:: bash
pip install --upgrade google-cloud-bigquery[pandas,pyarrow]
The following example demonstrates how to create a :class:`pandas.DataFrame`
and load it into a new table:
.. literalinclude:: ../samples/load_table_dataframe.py
:language: python
:dedent: 4
:start-after: [START bigquery_load_table_dataframe]
:end-before: [END bigquery_load_table_dataframe]
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