# Copyright 2021 Axis Communications AB.
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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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# http://www.apache.org/licenses/LICENSE-2.0
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"""Reduce datastructure."""
from jsontas.data_structures.datastructure import DataStructure
# pylint:disable=too-few-public-methods
[docs]class Reduce(DataStructure):
"""Reduce a list from end to beginning (from right) to a specific value
Example::
{
"reduced_list": {
"$reduce": {
"list": [
"element 1",
"element 2",
"element 3"
],
"to": 2
}
}
}
Result::
{
"reduced_list": [
"element 1",
"element 2"
]
}
"""
[docs] def execute(self):
"""Execute reduce.
:return: None and a list of values.
:rtype: tuple
"""
_list = self.data.get("list")
reduce_to_value = self.data.get("to", 1)
reduced_list = _list[:reduce_to_value]
return None, reduced_list