New in version 1.1.
Partition 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> list(sequencetools.partition_sequence_by_sign_of_elements(sequence))
[[0, 0], [-1, -1], [2, 3], [-5], [1, 2, 5], [-5, -6]]
abjad> list(sequencetools.partition_sequence_by_sign_of_elements(sequence, sign = [-1]))
[0, 0, [-1, -1], 2, 3, [-5], 1, 2, 5, [-5, -6]]
abjad> list(sequencetools.partition_sequence_by_sign_of_elements(sequence, sign = [0]))
[[0, 0], -1, -1, 2, 3, -5, 1, 2, 5, -5, -6]
abjad> list(sequencetools.partition_sequence_by_sign_of_elements(sequence, sign = [1]))
[0, 0, -1, -1, [2, 3], -5, [1, 2, 5], -5, -6]
abjad> list(sequencetools.partition_sequence_by_sign_of_elements(sequence, sign = [-1, 0]))
[[0, 0], [-1, -1], 2, 3, [-5], 1, 2, 5, [-5, -6]]
abjad> list(sequencetools.partition_sequence_by_sign_of_elements(sequence, sign = [-1, 1]))
[0, 0, [-1, -1], [2, 3], [-5], [1, 2, 5], [-5, -6]]
abjad> list(sequencetools.partition_sequence_by_sign_of_elements(sequence, sign = [0, 1]))
[[0, 0], -1, -1, [2, 3], -5, [1, 2, 5], -5, -6]
abjad> list(sequencetools.partition_sequence_by_sign_of_elements(sequence, sign = [-1, 0, 1]))
[[0, 0], [-1, -1], [2, 3], [-5], [1, 2, 5], [-5, -6]]
When -1 in sign, group negative elements.
When 0 in sign, group 0 elements.
When 1 in sign, group positive elements.
Return list of tuples of sequence element references.
Changed in version 2.0: renamed listtools.group_by_sign() to sequencetools.partition_sequence_by_sign_of_elements().