如何提取 DataArray 特定坐标元素答案

【问题标题】：How to Extract DataArray Specific Coordinates Element如何提取 DataArray 特定坐标元素
【发布时间】：2021-10-13 09:38:51
【问题描述】：

我有一个按季节（DJF、MAM、JJA、SON）组织的 xarray DataArray（形状为 4,481,1440 的season_means），我需要从这个数据数组中提取每个季节。 “season_means”看起来像这样：

season_means
Out[647]: 
<xarray.DataArray (season: 4, latitude: 481, longitude: 1440)>
array([[[3.73101167, 3.78266764, 3.84500943, ..., 3.58017382,
         3.6228325 , 3.67333682],
        [3.89038107, 3.93913177, 3.9947805 , ..., 3.76149173,
         3.78331248, 3.81462534],
        [4.09117172, 4.12262351, 4.16288429, ..., 3.83541736,
         3.96847398, 4.02620603],
        ...,
        [6.45479526, 6.46226879, 6.46740605, ..., 6.45008861,
         6.44926064, 6.45129207],
        [6.62904594, 6.637553  , 6.64926421, ..., 6.62020574,
         6.62031276, 6.62492512],
        [6.80419568, 6.81204775, 6.823688  , ..., 6.78878017,
         6.79085399, 6.79528929]],

       [[2.67082787, 2.6668227 , 2.66983277, ..., 2.66349807,
         2.66856487, 2.66961363],
        [2.55966305, 2.56259894, 2.57718152, ..., 2.5411451 ,
         2.54473561, 2.55051018],
        [2.43275311, 2.43219426, 2.43486259, ..., 2.3455072 ,
         2.42301587, 2.42563563],
...
        [7.03817834, 7.04312106, 7.04909586, ..., 7.03145763,
         7.02889831, 7.031519  ],
        [7.23051628, 7.23746768, 7.25118801, ..., 7.21922321,
         7.22061541, 7.22422635],
        [7.42557758, 7.435519  , 7.4491381 , ..., 7.41129483,
         7.41485019, 7.41830519]],

       [[3.18635784, 3.23346622, 3.28872645, ..., 3.03787274,
         3.09104232, 3.13880193],
        [3.18380067, 3.24283214, 3.30073143, ..., 3.01528357,
         3.05575926, 3.10097816],
        [3.21229531, 3.25513178, 3.30519563, ..., 2.96934209,
         3.08356936, 3.14385284],
        ...,
        [7.21287967, 7.20718457, 7.20604014, ..., 7.22531201,
         7.21654287, 7.21435037],
        [7.3609855 , 7.35768482, 7.36417584, ..., 7.37407895,
         7.36763059, 7.36305877],
        [7.51809654, 7.52212579, 7.52843031, ..., 7.52868904,
         7.52442108, 7.51974221]]])
Coordinates:
    number     int32 0
    step       timedelta64[ns] 00:00:00
    surface    float64 0.0
  * latitude   (latitude) float64 70.0 69.75 69.5 69.25 ... -49.5 -49.75 -50.0
  * longitude  (longitude) float64 -180.0 -179.8 -179.5 ... 179.2 179.5 179.8
  * season     (season) object 'DJF' 'JJA' 'MAM' 'SON'

我已经尝试了很多方法来仅提取每个季节以获得 (1, 481, 1440) 数据数组的形状，例如以下和我的错误消息。

season_means.groupby('season.DJF')
AttributeError: 'IndexVariable' object has no attribute 'DJF'
season_means.season.DJF
AttributeError: 'DataArray' object has no attribute 'DJF'
season_means.season(['DJF'])
TypeError: 'DataArray' object is not callable

谢谢！

【问题讨论】：

标签： python python-xarray

【解决方案1】：

我想我刚刚找到了答案-

season_means.loc[dict(season=slice('DJF','DJF'))]
Out[667]: 
<xarray.DataArray (season: 1, latitude: 481, longitude: 1440)>
array([[[3.73101167, 3.78266764, 3.84500943, ..., 3.58017382,
         3.6228325 , 3.67333682],
        [3.89038107, 3.93913177, 3.9947805 , ..., 3.76149173,
         3.78331248, 3.81462534],
        [4.09117172, 4.12262351, 4.16288429, ..., 3.83541736,
         3.96847398, 4.02620603],
        ...,
        [6.45479526, 6.46226879, 6.46740605, ..., 6.45008861,
         6.44926064, 6.45129207],
        [6.62904594, 6.637553  , 6.64926421, ..., 6.62020574,
         6.62031276, 6.62492512],
        [6.80419568, 6.81204775, 6.823688  , ..., 6.78878017,
         6.79085399, 6.79528929]]])
Coordinates:
    number     int32 0
    step       timedelta64[ns] 00:00:00
    surface    float64 0.0
  * latitude   (latitude) float64 70.0 69.75 69.5 69.25 ... -49.5 -49.75 -50.0
  * longitude  (longitude) float64 -180.0 -179.8 -179.5 ... 179.2 179.5 179.8
  * season     (season) object 'DJF'

【讨论】：