python-xarray - 如何在 Python 的 xarray.Dataset 中选择一些坐标？

Question

np.random.seed(0)
temperature = 15 + 8 * np.random.randn(2, 2, 3)
precipitation = 10 * np.random.rand(2, 2, 3)
lon = [[-99.83, -99.32], [-99.79, -99.23]]
lat = [[42.25, 42.21], [42.63, 42.59]]
time = pd.date_range("2014-09-06", periods=3)
reference_time = pd.Timestamp("2014-09-05")

ds = xr.Dataset(
    data_vars=dict(
        temperature=(["x", "y", "time"], temperature),
        precipitation=(["x", "y", "time"], precipitation),
    ),
    coords=dict(
        lon=(["x", "y"], lon),
        lat=(["x", "y"], lat),
        time=time,
        reference_time=reference_time,
    ),
    attrs=dict(description="Weather related data."),
)

ds
<xarray.Dataset>
Dimensions:         (time: 3, x: 2, y: 2)
Coordinates:
    lon             (x, y) float64 -99.83 -99.32 -99.79 -99.23
    lat             (x, y) float64 42.25 42.21 42.63 42.59
  * time            (time) datetime64[ns] 2014-09-06 2014-09-07 2014-09-08
    reference_time  datetime64[ns] 2014-09-05
Dimensions without coordinates: x, y
Data variables:
    temperature     (x, y, time) float64 29.11 18.2 22.83 ... 18.28 16.15 26.63
    precipitation   (x, y, time) float64 5.68 9.256 0.7104 ... 7.992 4.615 7.805
Attributes:
    description:  Weather related data.

在上面的示例数据集中，如果我运行ds.coords，它将显示“经度、纬度、时间和参考时间”。我怎样才能只得到 lon 和 lat？我失败了：

ds.coords[['lon', 'lat']]

标签： python-xarray

Answer 1

Dataset.__getitem__比 更灵活Dataset.coords.__getitem__，因为它可以接受列表作为参数。它也适用于坐标；即ds[[“lon”, “lat”]]应该做的伎俩。