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