Source code for pm4py.objects.log.util.filtering_utils

'''
PM4Py – A Process Mining Library for Python
Copyright (C) 2026 Process Intelligence Solutions GmbH

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License, or any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see this software project's root or
visit <https://www.gnu.org/licenses/>.

Website: https://processintelligence.solutions
Contact: info@processintelligence.solutions
'''
from pm4py.objects.log.obj import EventLog, Trace, Event
from copy import copy




def keep_one_trace_per_variant(log, parameters=None):
    """
    Keeps only one trace per variant (does not matter for basic inductive miner)

    Parameters
    --------------
    log
        Log
    parameters
        Parameters of the algorithm

    Returns
    --------------
    new_log
        Log (with one trace per variant)
    """
    if parameters is None:
        parameters = {}

    from pm4py.statistics.variants.log import get as variants_module

    new_log = EventLog()
    if log is not None:
        variants = variants_module.get_variants(log, parameters=parameters)
        for var in variants:
            curr_trace = variants[var][0]
            new_trace = Trace(attributes=copy(curr_trace.attributes))
            new_trace.attributes["@@num_traces"] = len(variants[var])
            for ev in curr_trace:
                new_trace.append(ev)
            new_log.append(new_trace)

    return new_log





def keep_only_one_attribute_per_event(log, attribute_key):
    """
    Keeps only one attribute per event

    Parameters
    ---------------
    log
        Event log
    attribute_key
        Attribute key
    """
    new_log = EventLog()
    if log is not None:
        for trace in log:
            new_trace = Trace()
            for ev in trace:
                new_trace.append(Event({attribute_key: ev[attribute_key]}))
            new_log.append(new_trace)

    return new_log