Auto Data Exploration and Feature Recommendation Tool

Machine learning (ML) projects typically start with a comprehensive exploration of the provided datasets. It is critical that ML practitioners to gain a deep understanding of:

• the properties of the data.
• the quality of the data.
• the potential predictive power of the data.

This process lays the groundwork for the subsequent feature selection and engineering steps, and it provides a solid foundation for building good ML models. Exploratory Data Analysis (EDA), feature selection, and engineering are often tied together and are important steps of the ML journey.

The objective of this tool is to perform comprehensive EDA, which includes

• Descriptive analysis of each attribute in a dataset for numerical, categorical
• Correlation analysis of two attributes (numerical versus numerical, numerical versus categorical, and categorical versus categorical) through qualitative and/or quantitative analysis.

The analysis results can be exported as a dictionary object, which can be loaded back for customized analysis. Based on the EDA performed, feature recommendations are made, and a summary report will be generated in markdown, html and pdf (if wkhtmltopdf is installed) formats. A snapshot of the sample report is as follows:

Google Cloud tools used:

• Google Cloud Platform (GCP) lets you build and host applications and websites, store data, and analyze data on Google's scalable infrastructure.
• Google BigQuery A fast, highly scalable, cost-effective, and fully managed cloud data warehouse for analytics, with even built-in machine learning.

Use the tool

bash run.sh \
    --key_file [KEY_FILE] \
    --data_source [DATA_SOURCE] \
    --preprocessing_backend [BACK_END] \
    --parallel_thread [NUM_PARALLEL] \
    --job_config [JOB_CONFIG_FILE] \
    --bq_table [BQ_TABLE] \
    --generated_job_config [TO_GENERATE] \
    --target_name [TARGET_ATTRIBUTE] \
    --target_type [TARGET_TYPE] \
    --report_path [REPORT_PATH] \
    --add_config_to_report [TO_ADD_CONFIG] \
    --export_result [TO_EXPORT_RESULT] \
    --sampling_rate [SAMPLING_RATE]

where:

• KEY_FILE, optional, string: Key file of the service account used to authenticate to the BigQuery API. If this is not specified, the GOOGLE_APPLICATION_CREDENTIALS from the environment variable will be used.
• DATA_SOURCE, optional, enum: Type of data source containing the training data. Currently only support BIGQUERY.
• BACK_END, optional, enum: Analysis computation backend. Currently only support BIGQUERY.
• NUM_PARALLEL, optional, int: Number of parallel queries issued to BACK_END.
• JOB_CONFIG_FILE, string: Configuration file containing the description of the datasource, and configurations of analysis.
• BQ_TABLE, string: BigQuery table name to be analyzed, in the format of [project.dataset.table].
• TARGET_ATTRIBUTE, optional, string: Name of attribute acting as target (label) in a ML problem.
• TARGET_TYPE, optional, enum: Data type of the target attribute, either Categorical or Numerical.
• TO_GENERATE, optional, boolean: Indicates whether the job config file should be regenerated from the datasource. If this is true, the generated job_config.ini will be saved at the path specified in JOB_CONFIG_FILE.
• REPORT_PATH, optional, string: Path of the folder for storing generated report.
• TO_ADD_CONFIG, optional, boolean, Indicates whether the job configuration will be added to the report.
• TO_EXPORT_RESULT, optional, boolean, Indicates whether the analysis result will be exported, which can be further load back for post analysis.
• SAMPLING_RATE, optional, float: the sampling rate used for statistical test.

One example is as follows:

bash run.sh \
    --generate_job_config True \
    --bq_table bigquery-public-data.ml_datasets.census_adult_income \
    --target_name race

Remarks

• TARGET_ATTRIBUTE and TARGET_TYPE will only take effect while generating job_config.ini from the datasource, i.e., TO_GENERATE is set True

Load exported analysis results

To help reload exported analysis results for further custom analysis, we have provided a utility function in result_loader.py to load exported analysis results to the format of {analysis_name: analysis_protobuf_object}. It is also possible to test the function by running from the top level folder as:

python3 -m ml_eda.result_loader --result_file <file_path>

Customize job_config.ini

It is possible to customize the job_config.ini if you want to

• Specify which attributes to analyze
• Control what analysis to performed
• Tune parameters for certain analysis

One example of the job_config.ini is as follows:

[DATASOURCE]
Type=BIGQUERY
Location=bigquery-public-data.ml_datasets.census_adult_income

[SCHEMA]
# If a column is integer type but categorical in nature, it should be assigned to categorical feature.
# The ml problem type will be determined by whether `Target` is in `NumericalFeatures` or `CategoricalFeatures`.

# Put `Null` if no target is required
Target=age
NumericalFeatures=age,hours_per_week,functional_weight,education_num
CategoricalFeatures=marital_status,race,education,native_country

[ANALYSIS.RUN]
# Control what analysis to run.
# By default, descriptive, histogram, value_counts, pearson_correlation will run.
# Others will be triggered by configuration.

# Qualitative Analysis
CONTINGENCY_TABLE.Run=True
TABLE_DESCRIPTIVE.Run=False

# Quantitative Analysis
PEARSON_CORRELATION.Run=True
INFORMATION_GAIN.Run=False
CHI_SQUARE.Run=False
ANOVA.Run=False

[ANALYSIS.CONFIG]
General.CardinalityLimit=20
HISTOGRAM.Bin=15
VALUE_COUNTS.Limit=15

Remarks

• A base version of the job_config.ini file can be regenerated from the datasource. And then further customization can be performed to perform desired analysis or tune parameters
• While generating job_config.ini from datasource, the datatype follows the attached convention. But, this can be definitely customized after the basic version of the job_config.ini is generated by the problem.
  • Integer -> Numerical
  • Float -> Numerical
  • Timestamp -> Numerical
  • String -> Categorical
  • Boolean -> Categorical
• Moreover, without customization of job_config.ini, only the following analysis will be run
  • Descriptive Analysis
  • Pearson Correlation
  • Information Gain

Supported Analysis

The supported analysis can be summarized here

• Descriptive Analysis
  • Missing values
  • Quantile statistics
  • Descriptive statistics
  • Distribution histogram
  • Cardinality
  • Unique counts
• Correlation Analysis
  • Qualitative Analysis
    • Contingency table
    • Descriptive table
  • Quantitative Analysis
    • Pearson correlation
    • Information gain
    • ANOVA
    • Chi-Square

Current Release

Current release is: 1.1

Change Logs

• Ensure Python3 runtime;
• Consistent numeric notation;
• Append job configuration to the final report;
• Performance improvement through parallel query execution;
• Generate different formats of report: markdown, html, pdf;
• Export analysis result as dictionary;
• Sample dataset for statistical test;

Contributors

• Shixin Luo
• Dan Anghel
• Barbara Fusinska