pandas-pyarrow 0.1.8

Description:

pandaspyarrow 0.1.8

pandas-pyarrow










pandas-pyarrow simplifies the conversion of pandas backend to pyarrow, allowing seamlessly switch to pyarrow pandas
backend.
Get started:
Installation
To install the package use pip:
pip install pandas-pyarrow

Usage
import pandas as pd

from pandas_pyarrow import convert_to_pyarrow

# Create a pandas DataFrame
df = pd.DataFrame({
'A': [1, 2, 3],
'B': ['a', 'b', 'c'],
'C': [1.1, 2.2, 3.3],
'D': [True, False, True]
})

# Convert the pandas DataFrame dtypes to arrow dtypes
adf: pd.DataFrame = convert_to_pyarrow(df)

print(adf.dtypes)

outputs:
A int64[pyarrow]
B string[pyarrow]
C double[pyarrow]
D bool[pyarrow]
dtype: object

Furthermore, it's possible to add mappings or override existing ones:
import pandas as pd

from pandas_pyarrow import PandasArrowConverter

# Create a pandas DataFrame
df = pd.DataFrame({
'A': [1, 2, 3],
'B': ['a', 'b', 'c'],
'C': [1.1, 2.2, 3.3],
'D': [True, False, True]
})

# Instantiate a PandasArrowConverter object
pandas_pyarrow_converter = PandasArrowConverter(
custom_mapper={'int64': 'int32[pyarrow]', 'float64': 'float32[pyarrow]'})

# Convert the pandas DataFrame dtypes to arrow dtypes
adf: pd.DataFrame = pandas_pyarrow_converter(df)

print(adf.dtypes)

outputs:
A int32[pyarrow]
B string[pyarrow]
C float[pyarrow]
D bool[pyarrow]
dtype: object

pandas-pyarrow also support db-dtypes used by bigquery python sdk:
pip install pandas-gbq

or
pip install pandas-pyarrow[bigquery]

import pandas_gbq as gbq

from pandas_pyarrow import PandasArrowConverter

# Specify the public dataset and table you want to query
dataset_id = "bigquery-public-data"
table_name = "hacker_news.stories"

# Construct the query string
query = """
SELECT * FROM `bigquery-public-data.austin_311.311_service_requests` LIMIT 1000
"""

# Use pandas_gbq to read the data from BigQuery
df = gbq.read_gbq(query)
pandas_pyarrow_converter = PandasArrowConverter()
adf = pandas_pyarrow_converter(df)
# Print the retrieved data
print(df.dtypes)
print(adf.dtypes)

outputs:
unique_key object
complaint_description object
source object
status object
status_change_date datetime64[us, UTC]
created_date datetime64[us, UTC]
last_update_date datetime64[us, UTC]
close_date datetime64[us, UTC]
incident_address object
street_number object
street_name object
city object
incident_zip Int64
county object
state_plane_x_coordinate object
state_plane_y_coordinate float64
latitude float64
longitude float64
location object
council_district_code Int64
map_page object
map_tile object
dtype: object
unique_key string[pyarrow]
complaint_description string[pyarrow]
source string[pyarrow]
status string[pyarrow]
status_change_date timestamp[us][pyarrow]
created_date timestamp[us][pyarrow]
last_update_date timestamp[us][pyarrow]
close_date timestamp[us][pyarrow]
incident_address string[pyarrow]
street_number string[pyarrow]
street_name string[pyarrow]
city string[pyarrow]
incident_zip int64[pyarrow]
county string[pyarrow]
state_plane_x_coordinate string[pyarrow]
state_plane_y_coordinate double[pyarrow]
latitude double[pyarrow]
longitude double[pyarrow]
location string[pyarrow]
council_district_code int64[pyarrow]
map_page string[pyarrow]
map_tile string[pyarrow]
dtype: object

Purposes

Simplify the conversion between pandas pyarrow and numpy backends.
Allow seamlessly switch to pyarrow pandas backend, even for problematic dtypes such float16 or db-dtypes.
dtype standardization for db-dtypes used by bigquery python sdk.

example:
import pandas as pd

# Create a pandas DataFrame
df = pd.DataFrame({

'C': [1.1, 2.2, 3.3],

}, dtype='float16')

df.convert_dtypes(dtype_backend='pyarrow')

will raise an error:
pyarrow.lib.ArrowNotImplementedError: Unsupported cast from halffloat to double using function cast_double

but with pandas-pyarrow:
import pandas as pd

from pandas_pyarrow import convert_to_pyarrow

# Create a pandas DataFrame
df = pd.DataFrame({

'C': [1.1, 2.2, 3.3],

}, dtype='float16')
adf = convert_to_pyarrow(df)
print(adf.dtypes)

outputs:
C halffloat[pyarrow]
dtype: object

Additional Information
When converting from higher precision numerical dtypes (like float64) to
lower precision (like float32), data precision might be compromised.