pydiverse-transform 0.1.5

Pipe based dataframe manipulation library that can also transform data on SQL databases

pydiverse.transform

Pipe based dataframe manipulation library that can also transform data on SQL databases

This is an early stage version 0.x which lacks documentation. Please contact https://github.com/orgs/pydiverse/teams/code-owners if you like to become an early adopter or to contribute early stage usage examples.

Usage

pydiverse.transform can either be installed via pypi with pip install pydiverse-transform or via conda-forge with conda install pydiverse-transform -c conda-forge.

Example

This code illustrates how to use pydiverse.transform with pandas and SQL:

from pydiverse.transform import Table
from pydiverse.transform.lazy import SQLTableImpl
from pydiverse.transform.eager import PandasTableImpl
from pydiverse.transform.core.verbs import *
import pandas as pd
import sqlalchemy as sa


def main():
    dfA = pd.DataFrame(
        {
            "x": [1],
            "y": [2],
        }
    )
    dfB = pd.DataFrame(
        {
            "a": [2, 1, 0, 1],
            "x": [1, 1, 2, 2],
        }
    )

    input1 = Table(PandasTableImpl("dfA", dfA))
    input2 = Table(PandasTableImpl("dfB", dfB))

    transform = (
        input1
        >> left_join(input2 >> select(), input1.x == input2.x)
        >> mutate(x5=input1.x * 5, a=input2.a)
    )
    out1 = transform >> collect()
    print("\nPandas based result:")
    print(out1)

    engine = sa.create_engine("sqlite:///:memory:")
    dfA.to_sql("dfA", engine, index=False, if_exists="replace")
    dfB.to_sql("dfB", engine, index=False, if_exists="replace")
    input1 = Table(SQLTableImpl(engine, "dfA"))
    input2 = Table(SQLTableImpl(engine, "dfB"))
    transform = (
        input1
        >> left_join(input2 >> select(), input1.x == input2.x)
        >> mutate(x5=input1.x * 5, a=input2.a)
    )
    out2 = transform >> collect()
    print("\nSQL query:")
    print(transform >> build_query())
    print("\nSQL based result:")
    print(out2)

    out1 = out1.sort_values("a").reset_index(drop=True)
    out2 = out2.sort_values("a").reset_index(drop=True)
    assert len(out1.compare(out2)) == 0


if __name__ == "__main__":
    main()