Add ExcelHandler

[amontanez24]

Problem Description

As a user, I'd like an streamlined way to load my data and metadata from files so that I can get right to using SDV.

Expected behavior

• In the sdv.io subpackage, add a folder called local
• In that folder add a class called ExcelHandler

__init__

Parameters

from sdv.io.local import ExcelHandlder

handler = ExcelHandler() 

read

Functionality

Internally, reading should use the read_excel function from pandas. A few things should be hardcoded by default

• Pandas should not detect an index column from the data
• Pandas should not try to infer datetime formats (or cast them to np.datetime objects). Any datetime column should be left as a dtype 'object'
• After reading the data, we should use it to infer a MultiTableMetadata object. (Even if there is only 1 table, we should still create a MultiTableMetadata object.)

Parameters

• (required) file_path: A string describing the path of the Excel file to read
• sheet_name: A list of strings denoting which sheets in the Excel file to read from
  • (default) None: Read all the sheets in the file
  • list(str): Read only the sheets listed

Returns

• data: A dictionary mapping each table name to a pandas DataFrame with the data. The table name is the same as the sheet name
• metadata: A MultiTableMetadata object that describes the data

write

Functionality
Internally, writing should use the to_excel function from pandas. A few things should be hardcoded by default

• Do not write the index column
• Each table of the synthetic data should be written as a new sheet within the file. The name of the sheet should be the same as the name of the table
• If a sheet already exists with the same name, completely override it

Parameters

• (required) synthetic_data: A dictionary that maps each table name to a pandas.DataFrame containing data from it

• (required) file_name: The name of the excel file to write

• sheet_name_suffix: A string with a suffix to add to each sheet name

  • (default) None: The name of the table should be the name of the sheet
  • (str) Append this string as the suffix. Eg. suffix of "_synthetic" will make sheets with "TABLENAME_synthetic"

• mode: A string signaling which mode of writing to use

  • (default) 'w': Write sheets to a new file, clearing any existing file that may exist
  • 'a': Append new sheets within the existing file. Note: You cannot append data to existing sheets.

Additional context

• We will add a number of local file handlers for different file types. Therefore the implementation of this class should also add a base class.
• Optionally, the init, read and write functions can include a subset of arguments that the corresponding pandas functions use
  • if both the read and write for pandas are the same for a parameter (eg. decimal), then put it in the init.
  • We can ignore most of these parameters. Only add ones that seem impactful