# Source code for featuretools.primitives.standard.aggregation.max_consecutive_zeros

```from woodwork.column_schema import ColumnSchema
from woodwork.logical_types import Double, Integer

from featuretools.primitives.base import AggregationPrimitive

[docs]class MaxConsecutiveZeros(AggregationPrimitive):
"""Determines the maximum number of consecutive zero values in the input

Args:
skipna (bool): Ignore any `NaN` values in the input. Default is True.

Examples:
>>> max_consecutive_zeros = MaxConsecutiveZeros()
>>> max_consecutive_zeros([1.0, -1.4, 0, 0.0, 0, -4.3])
3

`NaN` values can be ignored with the `skipna` parameter

>>> max_consecutive_zeros_skipna = MaxConsecutiveZeros(skipna=False)
>>> max_consecutive_zeros_skipna([1.0, -1.4, 0, None, 0.0, -4.3])
1
"""

name = "max_consecutive_zeros"
input_types = [
[ColumnSchema(logical_type=Integer)],
[ColumnSchema(logical_type=Double)],
]
return_type = ColumnSchema(logical_type=Integer, semantic_tags={"numeric"})
stack_on_self = False
default_value = 0

[docs]    def __init__(self, skipna=True):
self.skipna = skipna

def get_function(self):
def max_consecutive_zeros(x):
if self.skipna:
x = x.dropna()
# convert the numeric values to booleans for processing
x[x.notnull()] = x[x.notnull()].eq(0)
# find the locations where the value changes from the previous value
not_equal = x != x.shift()
# Use cumulative sum to determine where consecutive values occur. When the
# sum changes, consecutive non-zero values are present, when the cumulative
# sum remains unchnaged, consecutive zero values are present.
not_equal_sum = not_equal.cumsum()
# group the input by the cumulative sum values and use cumulative count
# to count the number of consecutive values. Add 1 to account for the cumulative
# sum starting at zero where the first zero occurs
consecutive = x.groupby(not_equal_sum).cumcount() + 1
# multiply by the boolean input to keep only the counts that correspond to
# zero values
consecutive_zero = consecutive * x
# return the max of all the consecutive zero values
return consecutive_zero.max()

return max_consecutive_zeros
```