def get_daily_events(da: xr.DataArray, da_value: float,
operator: str) -> xr.DataArray:
r"""Return a 0/1 mask when a condition is True or False.
the function returns 1 where operator(da, da_value) is True
0 where operator(da, da_value) is False
nan where da is nan
Parameters
----------
da : xr.DataArray
da_value : float
operator : {">", "<", ">=", "<=", "gt", "lt", "ge", "le"}
Logical operator {>, <, >=, <=, gt, lt, ge, le}. e.g. arr > thresh.
Returns
-------
xr.DataArray
"""
from xarray.core.ops import get_op
if operator in binary_ops:
op = binary_ops[operator]
elif operator in binary_ops.values():
op = operator
else:
raise ValueError(f"Operation `{operator}` not recognized.")
func = getattr(da, "_binary_op")(get_op(op))
events = func(da, da_value) * 1
events = events.where(~(np.isnan(da)))
events = events.rename("events")
return events
def threshold_count(
da: xr.DataArray, op: str, thresh: float, freq: str
) -> xr.DataArray:
"""Count number of days above or below threshold.
Parameters
----------
da : xr.DataArray
Input data.
op : str
Logical operator {>, <, >=, <=, gt, lt, ge, le }. e.g. arr > thresh.
thresh : float
Threshold value.
freq : str
Resampling frequency defining the periods
defined in http://pandas.pydata.org/pandas-docs/stable/timeseries.html#resampling.
Returns
-------
xr.DataArray
The number of days meeting the constraints for each period.
"""
from xarray.core.ops import get_op
if op in binary_ops:
op = binary_ops[op]
elif op in binary_ops.values():
pass
else:
raise ValueError(f"Operation `{op}` not recognized.")
func = getattr(da, "_binary_op")(get_op(op))
c = func(da, thresh) * 1
return c.resample(time=freq).sum(dim="time")
def compare(da: xr.DataArray, op: str, thresh: Union[float,
int]) -> xr.DataArray:
"""Compare a dataArray to a threshold using given operator.
Parameters
----------
da : xr.DataArray
Input data.
op : {">", "<", ">=", "<=", "gt", "lt", "ge", "le"}
Logical operator {>, <, >=, <=, gt, lt, ge, le }. e.g. arr > thresh.
thresh : Union[float, int]
Threshold value.
Returns
-------
xr.DataArray
Boolean mask of the comparison.
"""
from xarray.core.ops import get_op
if op in binary_ops:
op = binary_ops[op]
elif op in binary_ops.values():
pass
else:
raise ValueError(f"Operation `{op}` not recognized.")
func = getattr(da, "_binary_op")(get_op(op))
return func(da, thresh)
