Build fieldlist from dicts in a loop

Distinct latitudes/longitudes

In this example each field is defined by a dict using generic metadata keys. The latitudes and longitudes specified as disctinct values, the 2D field geometry will be automatically built from them.

[1]:

prototype = {
        "latitudes": [10.0, 0.0, -10.0],
        "longitudes": [20, 40.0],
        "values": [1, 2, 3, 4, 5, 6],
        "valid_datetime": "2018-08-01T09:00:00Z",
    }

d = [
        {"param": "t", "level": 500, **prototype},
        {"param": "t", "level": 850, **prototype},
        {"param": "u", "level": 500, **prototype},
        {"param": "u", "level": 850, **prototype},
        {"param": "d", "level": 850, **prototype},
        {"param": "d", "level": 600, **prototype},
    ]

Create a fieldlist from the data above in a loop.

[2]:

from earthkit.data import ArrayField
from earthkit.data import SimpleFieldList

ds = SimpleFieldList()
for f in d:
    ds.append(ArrayField(f["values"], f))

[3]:

ds.ls()

[3]:

	param	level	base_datetime	valid_datetime	step	number
0	t	500	None	2018-08-01T09:00:00+00:00	None	None
1	t	850	None	2018-08-01T09:00:00+00:00	None	None
2	u	500	None	2018-08-01T09:00:00+00:00	None	None
3	u	850	None	2018-08-01T09:00:00+00:00	None	None
4	d	850	None	2018-08-01T09:00:00+00:00	None	None
5	d	600	None	2018-08-01T09:00:00+00:00	None	None

[4]:

ds[0].to_latlon()

[4]:

{'lat': array([[ 10.,  10.],
        [  0.,   0.],
        [-10., -10.]]),
 'lon': array([[20., 40.],
        [20., 40.],
        [20., 40.]])}

[5]:

ds[0].grid_points()

[5]:

(array([ 10.,  10.,   0.,   0., -10., -10.]),
 array([20., 40., 20., 40., 20., 40.]))

[6]:

ds.to_numpy()

[6]:

array([[[1, 2],
        [3, 4],
        [5, 6]],

       [[1, 2],
        [3, 4],
        [5, 6]],

       [[1, 2],
        [3, 4],
        [5, 6]],

       [[1, 2],
        [3, 4],
        [5, 6]],

       [[1, 2],
        [3, 4],
        [5, 6]],

       [[1, 2],
        [3, 4],
        [5, 6]]])

[7]:

ds.metadata("level")

[7]:

[500, 850, 500, 850, 850, 600]

[8]:

ds[0].metadata().valid_datetime()

[8]:

datetime.datetime(2018, 8, 1, 9, 0, tzinfo=tzutc())

[9]:

ds[0].mars_grid

[9]:

[20.0, 10.0]

[10]:

ds.sel(param="t").ls()

[10]:

	param	level	base_datetime	valid_datetime	step	number
0	t	500	None	2018-08-01T09:00:00+00:00	None	None
1	t	850	None	2018-08-01T09:00:00+00:00	None	None

[11]:

ds.order_by("level").ls()

[11]:

	param	level	base_datetime	valid_datetime	step	number
0	t	500	None	2018-08-01T09:00:00+00:00	None	None
1	u	500	None	2018-08-01T09:00:00+00:00	None	None
2	d	600	None	2018-08-01T09:00:00+00:00	None	None
3	t	850	None	2018-08-01T09:00:00+00:00	None	None
4	u	850	None	2018-08-01T09:00:00+00:00	None	None
5	d	850	None	2018-08-01T09:00:00+00:00	None	None

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