FCCgroup

FCCgroup is a Python package for grouping chemicals with three complementary methods:

• Structural pattern matching with SMARTS fingerprints
• Functional list matching against packaged reference lists
• Regex-based grouping from chemical names and formulas

The package is developed under the organization of Food Packaging Forum. Authored by Albert Anguera Sempere and Helene Wiesinger.

Features

• Structural classification using SMARTS fingerprints
• Functional list matching from packaged assets
• Regex-based classification from names and formulas
• Automatic CompTox enrichment when selected methods require missing fields
• Flexible method selection through GroupingConfig(methods=...)
• Optional SMARTS fingerprint subsetting via GroupingConfig(smarts_fingerprints=...)
• Package data bundled under fccgroup/assets

Installation

Install from PyPI:

pip install fccgroup

Install from source:

git clone https://github.com/Food-Packaging-Forum/fccgroup.git
cd fccgroup
pip install -e .

Install development dependencies:

pip install -e .[dev]

Quick Start

import pandas as pd

from fccgroup import ChemicalGrouper, ColumnMapping, GroupingConfig, GroupingMethod

df = pd.DataFrame(
  {
    "CASRN": ["74-84-0"],
    "Structure": ["CC"],
    "Name": ["ethane"],
    "IUPAC": ["ethane"],
    "Formula": ["C2H6"],
  }
)

config = GroupingConfig(
  methods=[GroupingMethod.SMARTS, GroupingMethod.REGEX],
  column_mapping=ColumnMapping(
    cas="CASRN",
    smiles="Structure",
    name_columns=["Name", "IUPAC"],
    formula="Formula",
  ),
)

grouper = ChemicalGrouper(df=df, grouping_config=config)
results = grouper.group_chemicals(save=False)

# Columns are a MultiIndex: (group_label, column_name)
print(results.columns.tolist())
print(results.head())

Selecting Grouping Methods

FCCgroup does not expose a GroupingMode enum. Method selection is configured with GroupingMethod values:

• GroupingMethod.SMARTS: structural pattern matching
• GroupingMethod.LISTS: functional list matching
• GroupingMethod.REGEX: regex-based grouping from names and formulas

Common configurations:

GroupingConfig(methods=[GroupingMethod.SMARTS], column_mapping=...)
GroupingConfig(methods=[GroupingMethod.SMARTS, GroupingMethod.LISTS], column_mapping=...)
GroupingConfig(
  methods=[GroupingMethod.SMARTS, GroupingMethod.LISTS, GroupingMethod.REGEX],
  column_mapping=...,
)

Filtering SMARTS fingerprints

To apply only a subset of the ~400 bundled SMARTS patterns, pass their names to smarts_fingerprints:

GroupingConfig(
  methods=[GroupingMethod.SMARTS],
  column_mapping=...,
  smarts_fingerprints={"Alkanes", "PAH derivatives hydrocarbon"},
)

When smarts_fingerprints is None (default), all available patterns are applied.

Custom assets path

By default ChemicalGrouper loads assets from the package installation directory. To point it at a different directory:

ChemicalGrouper(df=df, grouping_config=config, assets_path="/path/to/custom/assets")

Input Requirements

• ChemicalGrouper must be initialized with a non-empty pandas DataFrame.
• ColumnMapping must provide at least one of cas or smiles (the other may be None).
• name_columns and formula are optional at configuration time, but REGEX grouping may trigger CompTox enrichment when they are missing.
• Input column names can be custom; FCCgroup maps them to canonical internal fields.

Assets And External Services

• Packaged assets live under fccgroup/assets.
• Mapping.xlsx and the files in fccgroup/assets/lists are required for LISTS workflow.
• CompTox (EPA) is used only when the selected methods require fields that are not already available in the mapped input columns (e.g. SMILES needed for SMARTS but only CAS provided).
• CompTox enrichment requires a valid API key set in the COMPTOX_API_KEY environment variable.
• CompTox usage depends on network availability and the EPA CompTox service.

Output

group_chemicals(save=True) returns a pandas DataFrame with a MultiIndex on columns. The first level groups results by method; the second level is the column name.

Example column access:

# Access the SMILES identifier column
results[("Identifier", "SMILES")]

# Access the Chemical groups column
results[("Structural patterns", "Chemical groups")]

When save=True (default), results are also written to an Excel file in the current working directory.

Runtime Dependencies

FCCgroup currently declares the runtime dependencies described in requirements.txt

Citation

If you use FCCgroup in your research, please cite:

@software{fccgroup,
  title={FCCgroup: Chemical Grouping and Classification Package},
  author={Anguera Sempere, Albert and Wiesinger, Helene},
  organization={Food Packaging Forum},
  year={2026},
}

Contributing

Contributions are welcome through pull requests.

Support

For issues, questions, or suggestions, open an issue at https://github.com/Food-Packaging-Forum/fccgroup/issues.

License

Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0). See LICENSE for details.

Disclaimer

This software is provided "as is", without warranties of any kind, express or implied. To the maximum extent permitted by applicable law, Food Packaging Forum and contributors shall not be liable for any direct, indirect, incidental, special, exemplary, or consequential damages arising from the use or misuse of this software.