New in version 1.1.
Sum consecutive sequence elements by sign:
abjad> from abjad.tools import sequencetools
abjad> sequence = [0, 0, -1, -1, 2, 3, -5, 1, 2, 5, -5, -6]
abjad> sequencetools.sum_consecutive_sequence_elements_by_sign(sequence)
[0, -2, 5, -5, 8, -11]
abjad> sequencetools.sum_consecutive_sequence_elements_by_sign(sequence, sign = [-1])
[0, 0, -2, 2, 3, -5, 1, 2, 5, -11]
abjad> sequencetools.sum_consecutive_sequence_elements_by_sign(sequence, sign = [0])
[0, -1, -1, 2, 3, -5, 1, 2, 5, -5, -6]
abjad> sequencetools.sum_consecutive_sequence_elements_by_sign(sequence, sign = [1])
[0, 0, -1, -1, 5, -5, 8, -5, -6]
abjad> sequencetools.sum_consecutive_sequence_elements_by_sign(sequence, sign = [-1, 0])
[0, -2, 2, 3, -5, 1, 2, 5, -11]
abjad> sequencetools.sum_consecutive_sequence_elements_by_sign(sequence, sign = [-1, 1])
[0, 0, -2, 5, -5, 8, -11]
abjad> sequencetools.sum_consecutive_sequence_elements_by_sign(sequence, sign = [0, 1])
[0, -1, -1, 5, -5, 8, -5, -6]
abjad> sequencetools.sum_consecutive_sequence_elements_by_sign(sequence, sign = [-1, 0, 1])
[0, -2, 5, -5, 8, -11]
When -1 in sign, sum consecutive negative elements.
When 0 in sign, sum consecutive 0 elements.
When 1 in sign, sum consecutive positive elements.
Return list.
Changed in version 2.0: renamed sequencetools.sum_by_sign() to sequencetools.sum_consecutive_sequence_elements_by_sign().