mirror of https://github.com/ecmwf/eccodes.git
95 lines
2.3 KiB
Python
95 lines
2.3 KiB
Python
#
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# (C) Copyright 2005- ECMWF.
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#
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# This software is licensed under the terms of the Apache Licence Version 2.0
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# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
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#
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# In applying this licence, ECMWF does not waive the privileges and immunities
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# granted to it by virtue of its status as an intergovernmental organisation
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# nor does it submit to any jurisdiction.
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#
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# Description: How to create and use an index to access GRIB messages from
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# a file
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from __future__ import print_function
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import traceback
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import sys
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import os
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from eccodes import *
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INPUT = '../../data/index.grib'
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VERBOSE = 1 # verbose error reporting
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def product(*args, **kwds):
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# product('ABCD', 'xy') --> Ax Ay Bx By Cx Cy Dx Dy
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# product(range(2), repeat=3) --> 000 001 010 011 100 101 110 111
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pools = list(map(tuple, args)) * kwds.get('repeat', 1)
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result = [[]]
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for pool in pools:
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result = [x + [y] for x in result for y in pool]
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for prod in result:
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yield tuple(prod)
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def example():
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index_keys = ["shortName", "level", "number", "step"]
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index_file = "my.idx"
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iid = None
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if os.path.exists(index_file):
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iid = codes_index_read(index_file)
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else:
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iid = codes_index_new_from_file(INPUT, index_keys)
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# multiple files can be added to an index:
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# codes_index_add_file(iid,"grib file to add")
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codes_index_write(iid, index_file)
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index_vals = []
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for key in index_keys:
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print("%sSize=%d" % (
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key,
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codes_index_get_size(iid, key)
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))
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key_vals = codes_index_get(iid, key)
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print(" ".join(key_vals))
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index_vals.append(key_vals)
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for prod in product(*index_vals):
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for i in range(len(index_keys)):
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codes_index_select(iid, index_keys[i], prod[i])
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while 1:
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gid = codes_new_from_index(iid)
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if gid is None:
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break
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print(" ".join(["%s=%s" % (key, codes_get(gid, key))
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for key in index_keys]))
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codes_release(gid)
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codes_index_release(iid)
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def main():
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try:
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example()
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except CodesInternalError as err:
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if VERBOSE:
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traceback.print_exc(file=sys.stderr)
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else:
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sys.stderr.write(err.msg + '\n')
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return 1
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if __name__ == "__main__":
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sys.exit(main())
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