The following reduction functions receive a "where" argument: - https://numpy.org/doc/stable/reference/generated/numpy.max.html - https://numpy.org/doc/stable/reference/generated/numpy.min.html - https://numpy.org/doc/stable/reference/generated/numpy.sum.html - https://numpy.org/doc/stable/reference/generated/numpy.prod.html - https://numpy.org/doc/stable/reference/generated/numpy.mean.html - https://numpy.org/doc/stable/reference/generated/numpy.var.html - https://numpy.org/doc/stable/reference/generated/numpy.std.html and their nan* counterparts, where applicable. Feature request: Add "where" argument to - https://numpy.org/doc/stable/reference/generated/numpy.ptp.html - https://numpy.org/doc/stable/reference/generated/numpy.average.html - https://numpy.org/doc/stable/reference/generated/numpy.median.html - https://numpy.org/doc/stable/reference/generated/numpy.quantile.html - https://numpy.org/doc/stable/reference/generated/numpy.percentile.html - https://numpy.org/doc/stable/reference/generated/numpy.nanmedian.html and their nan* counterparts, where applicable. ptp should be especially straightforward, since it's just max - min.