Metadata-Version: 2.1
Name: datacompy
Version: 0.7.3
Summary: Dataframe comparison in Python
Home-page: https://github.com/capitalone/datacompy
License: Apache-2.0
Description: .. image:: https://github.com/capitalone/datacompy/workflows/Python%20package/badge.svg
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        =========
        DataComPy
        =========
        
        DataComPy is a package to compare two Pandas DataFrames. Originally started to
        be something of a replacement for SAS's ``PROC COMPARE`` for Pandas DataFrames
        with some more functionality than just ``Pandas.DataFrame.equals(Pandas.DataFrame)``
        (in that it prints out some stats, and lets you tweak how accurate matches have to be).
        Then extended to carry that functionality over to Spark Dataframes.
        
        Quick Installation
        ==================
        
        ::
        
            pip install datacompy
        
        Pandas Detail
        =============
        
        DataComPy will try to join two dataframes either on a list of join columns, or
        on indexes.  If the two dataframes have duplicates based on join values, the
        match process sorts by the remaining fields and joins based on that row number.
        
        Column-wise comparisons attempt to match values even when dtypes don't match.
        So if, for example, you have a column with ``decimal.Decimal`` values in one
        dataframe and an identically-named column with ``float64`` dtype in another,
        it will tell you that the dtypes are different but will still try to compare the
        values.
        
        Basic Usage
        -----------
        
        .. code-block:: python
        
            from io import StringIO
            import pandas as pd
            import datacompy
        
            data1 = """acct_id,dollar_amt,name,float_fld,date_fld
            10000001234,123.45,George Maharis,14530.1555,2017-01-01
            10000001235,0.45,Michael Bluth,1,2017-01-01
            10000001236,1345,George Bluth,,2017-01-01
            10000001237,123456,Bob Loblaw,345.12,2017-01-01
            10000001239,1.05,Lucille Bluth,,2017-01-01
            """
        
            data2 = """acct_id,dollar_amt,name,float_fld
            10000001234,123.4,George Michael Bluth,14530.155
            10000001235,0.45,Michael Bluth,
            10000001236,1345,George Bluth,1
            10000001237,123456,Robert Loblaw,345.12
            10000001238,1.05,Loose Seal Bluth,111
            """
        
            df1 = pd.read_csv(StringIO(data1))
            df2 = pd.read_csv(StringIO(data2))
        
            compare = datacompy.Compare(
                df1,
                df2,
                join_columns='acct_id',  #You can also specify a list of columns
                abs_tol=0, #Optional, defaults to 0
                rel_tol=0, #Optional, defaults to 0
                df1_name='Original', #Optional, defaults to 'df1'
                df2_name='New' #Optional, defaults to 'df2'
                )
            compare.matches(ignore_extra_columns=False)
            # False
        
            # This method prints out a human-readable report summarizing and sampling differences
            print(compare.report())
        
        See docs for more detailed usage instructions and an example of the report output.
        
        Things that are happening behind the scenes
        -------------------------------------------
        
        - You pass in two dataframes (``df1``, ``df2``) to ``datacompy.Compare`` and a
          column to join on (or list of columns) to ``join_columns``.  By default the
          comparison needs to match values exactly, but you can pass in ``abs_tol``
          and/or ``rel_tol`` to apply absolute and/or relative tolerances for numeric columns.
        
          - You can pass in ``on_index=True`` instead of ``join_columns`` to join on
            the index instead.
        
        - The class validates that you passed dataframes, that they contain all of the
          columns in `join_columns` and have unique column names other than that.  The
          class also lowercases all column names to disambiguate.
        - On initialization the class validates inputs, and runs the comparison.
        - ``Compare.matches()`` will return ``True`` if the dataframes match, ``False``
          otherwise.
        
          - You can pass in ``ignore_extra_columns=True`` to not return ``False`` just
            because there are non-overlapping column names (will still check on
            overlapping columns)
          - NOTE: if you only want to validate whether a dataframe matches exactly or
            not, you should look at ``pandas.testing.assert_frame_equal``.  The main
            use case for ``datacompy`` is when you need to interpret the difference
            between two dataframes.
        
        - Compare also has some shortcuts like
        
          - ``intersect_rows``, ``df1_unq_rows``, ``df2_unq_rows`` for getting
            intersection, just df1 and just df2 records (DataFrames)
          - ``intersect_columns()``, ``df1_unq_columns()``, ``df2_unq_columns()`` for
            getting intersection, just df1 and just df2 columns (Sets)
        
        - You can turn on logging to see more detailed logs.
        
        
        .. _spark-detail:
        
        Spark Detail
        ============
        
        DataComPy's ``SparkCompare`` class will join two dataframes either on a list of join
        columns. It has the capability to map column names that may be different in each
        dataframe, including in the join columns. You are responsible for creating the
        dataframes from any source which Spark can handle and specifying a unique join
        key. If there are duplicates in either dataframe by join key, the match process
        will remove the duplicates before joining (and tell you how many duplicates were
        found).
        
        As with the Pandas-based ``Compare`` class, comparisons will be attempted even
        if dtypes don't match. Any schema differences will be reported in the output
        as well as in any mismatch reports, so that you can assess whether or not a
        type mismatch is a problem or not.
        
        The main reasons why you would choose to use ``SparkCompare`` over ``Compare``
        are that your data is too large to fit into memory, or you're comparing data
        that works well in a Spark environment, like partitioned Parquet, CSV, or JSON
        files, or Cerebro tables.
        
        Performance Implications
        ------------------------
        
        Spark scales incredibly well, so you can use ``SparkCompare`` to compare
        billions of rows of data, provided you spin up a big enough cluster. Still,
        joining billions of rows of data is an inherently large task, so there are a
        couple of things you may want to take into consideration when getting into the
        cliched realm of "big data":
        
        * ``SparkCompare`` will compare all columns in common in the dataframes and
          report on the rest. If there are columns in the data that you don't care to
          compare, use a ``select`` statement/method on the dataframe(s) to filter
          those out. Particularly when reading from wide Parquet files, this can make
          a huge difference when the columns you don't care about don't have to be
          read into memory and included in the joined dataframe.
        * For large datasets, adding ``cache_intermediates=True`` to the ``SparkCompare``
          call can help optimize performance by caching certain intermediate dataframes
          in memory, like the de-duped version of each input dataset, or the joined
          dataframe. Otherwise, Spark's lazy evaluation will recompute those each time
          it needs the data in a report or as you access instance attributes. This may
          be fine for smaller dataframes, but will be costly for larger ones. You do
          need to ensure that you have enough free cache memory before you do this, so
          this parameter is set to False by default.
        
        Basic Usage
        -----------
        
        .. code-block:: python
        
            import datetime
            import datacompy
            from pyspark.sql import Row
        
            # This example assumes you have a SparkSession named "spark" in your environment, as you
            # do when running `pyspark` from the terminal or in a Databricks notebook (Spark v2.0 and higher)
        
            data1 = [
                Row(acct_id=10000001234, dollar_amt=123.45, name='George Maharis', float_fld=14530.1555,
                    date_fld=datetime.date(2017, 1, 1)),
                Row(acct_id=10000001235, dollar_amt=0.45, name='Michael Bluth', float_fld=1.0,
                    date_fld=datetime.date(2017, 1, 1)),
                Row(acct_id=10000001236, dollar_amt=1345.0, name='George Bluth', float_fld=None,
                    date_fld=datetime.date(2017, 1, 1)),
                Row(acct_id=10000001237, dollar_amt=123456.0, name='Bob Loblaw', float_fld=345.12,
                    date_fld=datetime.date(2017, 1, 1)),
                Row(acct_id=10000001239, dollar_amt=1.05, name='Lucille Bluth', float_fld=None,
                    date_fld=datetime.date(2017, 1, 1))
            ]
        
            data2 = [
                Row(acct_id=10000001234, dollar_amt=123.4, name='George Michael Bluth', float_fld=14530.155),
                Row(acct_id=10000001235, dollar_amt=0.45, name='Michael Bluth', float_fld=None),
                Row(acct_id=10000001236, dollar_amt=1345.0, name='George Bluth', float_fld=1.0),
                Row(acct_id=10000001237, dollar_amt=123456.0, name='Robert Loblaw', float_fld=345.12),
                Row(acct_id=10000001238, dollar_amt=1.05, name='Loose Seal Bluth', float_fld=111.0)
            ]
        
            base_df = spark.createDataFrame(data1)
            compare_df = spark.createDataFrame(data2)
        
            comparison = datacompy.SparkCompare(spark, base_df, compare_df, join_columns=['acct_id'])
        
            # This prints out a human-readable report summarizing differences
            comparison.report()
        
        Using SparkCompare on EMR or standalone Spark
        ---------------------------------------------
        
        1. Set proxy variables
        2. Create a virtual environment, if desired (``virtualenv venv; source venv/bin/activate``)
        3. Pip install datacompy and requirements
        4. Ensure your SPARK_HOME environment variable is set (this is probably ``/usr/lib/spark`` but may
           differ based on your installation)
        5. Augment your PYTHONPATH environment variable with
           ``export PYTHONPATH=$SPARK_HOME/python/lib/py4j-0.10.4-src.zip:$SPARK_HOME/python:$PYTHONPATH``
           (note that your version of py4j may differ depending on the version of Spark you're using)
        
        
        Using SparkCompare on Databricks
        --------------------------------
        
        1. Clone this repository locally
        2. Create a datacompy egg by running ``python setup.py bdist_egg`` from the repo root directory.
        3. From the Databricks front page, click the "Library" link under the "New" section.
        4. On the New library page:
            a. Change source to "Upload Python Egg or PyPi"
            b. Under "Upload Egg", Library Name should be "datacompy"
            c. Drag the egg file in datacompy/dist/ to the "Drop library egg here to upload" box
            d. Click the "Create Library" button
        5. Once the library has been created, from the library page (which you can find in your /Users/{login} workspace),
           you can choose clusters to attach the library to.
        6. ``import datacompy`` in a notebook attached to the cluster that the library is attached to and enjoy!
        
        Contributors
        ------------
        
        We welcome and appreciate your contributions! Before we can accept any contributions, we ask that you please be sure to
        sign the `Contributor License Agreement (CLA) <https://cla-assistant.io/capitalone/datacompy>`_.
        
        This project adheres to the `Open Source Code of Conduct <https://developer.capitalone.com/resources/code-of-conduct/>`_.
        By participating, you are expected to honor this code.
        
        
        Roadmap
        -------
        
        Roadmap details can be found `here <https://github.com/capitalone/datacompy/blob/develop/ROADMAP.rst>`_
Platform: UNKNOWN
Provides-Extra: spark
Provides-Extra: docs
Provides-Extra: tests
Provides-Extra: qa
Provides-Extra: build
Provides-Extra: dev
