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source: flex_extract.git/Source/Python/Classes/GribUtil.py @ 8463d78

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Last change on this file since 8463d78 was 8463d78, checked in by Anne Philipp <anne.philipp@…>, 5 years ago
made python3 again, now working
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1	#!/usr/bin/env python3
2	# -- coding: utf-8 --
3	#*******************************************************************************
4	# @Author: Anne Fouilloux (University of Oslo)
5	#
6	# @Date: July 2014
7	#
8	# @Change History:
9	# February 2018 - Anne Philipp (University of Vienna):
10	# - applied PEP8 style guide
11	# - added documentation
12	# - changed some naming
13	#
14	# @License:
15	# (C) Copyright 2014-2018.
16	#
17	# This software is licensed under the terms of the Apache Licence Version 2.0
18	# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
19	#
20	# @Class Description:
21	# The GRIB API provides all necessary tools to work directly with the
22	# grib files. Nevertheless, the GRIB API tools are very basic and are in
23	# direct connection with the grib files. This class provides some higher
24	# functions which apply a set of GRIB API tools together in the respective
25	# context. So, the class initially contains a list of grib files (their
26	# names) and the using program then applies the methods directly on the
27	# class objects without having to think about how the actual GRIB API
28	# tools have to be arranged.
29	#
30	# @Class Content:
31	# - __init__
32	# - get_keys
33	# - set_keys
34	# - copy_dummy_msg
35	# - index
36	#
37	# @Class Attributes:
38	# - filenames
39	#
40	#*******************************************************************************
41
42	# ------------------------------------------------------------------------------
43	# MODULES
44	# ------------------------------------------------------------------------------
45	from __future__ import print_function
46
47	import os
48
49	# ------------------------------------------------------------------------------
50	# CLASS
51	# ------------------------------------------------------------------------------
52	class GribUtil(object):
53	'''
54	Class for GRIB utilities (new methods) based on GRIB API
55	'''
56	# --------------------------------------------------------------------------
57	# CLASS FUNCTIONS
58	# --------------------------------------------------------------------------
59	def __init__(self, filenames):
60	'''Initialise an object of GribUtil and assign a list of filenames.
61
62	Parameters
63	----------
64	filenames : :obj:`list` of :obj:`strings`
65	A list of filenames.
66
67	Return
68	------
69
70	'''
71
72	self.filenames = filenames
73
74	return
75
76
77	def get_keys(self, keynames, wherekeynames=[], wherekeyvalues=[]):
78	'''Get keyvalues for a given list of keynames a where statement
79	can be given (list of key and list of values)
80
81	Parameters
82	----------
83	keynames : :obj:`list` of :obj:`string`
84	List of keynames.
85
86	wherekeynames : :obj:`list` of :obj:`string`, optional
87	Default value is an empty list.
88
89	wherekeyvalues : :obj:`list` of :obj:`string`, optional
90	Default value is an empty list.
91
92	Return
93	------
94	return_list : :obj:`list` of :obj:`string`
95	List of keyvalues for given keynames.
96	'''
97	from eccodes import (codes_new_from_file, codes_is_defined, codes_get,
98	codes_release)
99
100	fileid = open(self.filenames, 'r')
101
102	return_list = []
103
104	while 1:
105	gid = codes_new_from_file(fileid)
106
107	if gid is None:
108	break
109
110	if len(wherekeynames) != len(wherekeyvalues):
111	raise Exception("Number of key values and key names must be \
112	the same. Give a value for each keyname!")
113
114	select = True
115	i = 0
116	for wherekey in wherekeynames:
117	if not codes_is_defined(gid, wherekey):
118	raise Exception("where key was not defined")
119
120	select = (select and (str(wherekeyvalues[i]) ==
121	str(codes_get(gid, wherekey))))
122	i += 1
123
124	if select:
125	llist = []
126	for key in keynames:
127	llist.extend([str(codes_get(gid, key))])
128	return_list.append(llist)
129
130	codes_release(gid)
131
132	fileid.close()
133
134	return return_list
135
136
137	def set_keys(self, fromfile, keynames, keyvalues, wherekeynames=[],
138	wherekeyvalues=[], strict=False, filemode='w'):
139	'''Opens the file to read the grib messages and then write
140	the selected messages (with wherekeys) to a new output file.
141	Also, the keyvalues of the passed list of keynames are set.
142
143	Parameters
144	----------
145	fromfile : :obj:`string`
146	Filename of the input file to read the grib messages from.
147
148	keynames : :obj:`list` of :obj:`string`
149	List of keynames to set in the selected messages.
150	Default is an empty list.
151
152	keyvalues : :obj:`list` of :obj:`string`
153	List of keyvalues to set in the selected messages.
154	Default is an empty list.
155
156	wherekeynames : :obj:`list` of :obj:`string`, optional
157	List of keynames to select correct message.
158	Default value is an empty list.
159
160	wherekeyvalues : :obj:`list` of :obj:`string`, optional
161	List of keyvalues for keynames to select correct message.
162	Default value is an empty list.
163
164	strict : :obj:`boolean`, optional
165	Decides if everything from keynames and keyvalues
166	is written out the grib file (False) or only those
167	meeting the where statement (True). Default is False.
168
169	filemode : :obj:`string`, optional
170	Sets the mode for the output file. Default is "w".
171
172	Return
173	------
174
175	'''
176	from eccodes import (codes_grib_new_from_file, codes_is_defined,
177	codes_get, codes_set, codes_write,
178	codes_set_values, codes_release)
179
180	if len(wherekeynames) != len(wherekeyvalues):
181	raise Exception("Give a value for each keyname!")
182
183	fout = open(self.filenames, filemode)
184	fin = open(fromfile)
185
186	while 1:
187	gid = codes_grib_new_from_file(fin)
188
189	if gid is None:
190	break
191
192	select = True
193	i = 0
194	for wherekey in wherekeynames:
195	if not codes_is_defined(gid, wherekey):
196	raise Exception("wherekey was not defined")
197
198	select = (select and (str(wherekeyvalues[i]) ==
199	str(codes_get(gid, wherekey))))
200	i += 1
201
202	if select:
203	i = 0
204	for key in keynames:
205	if key == 'values':
206	codes_set_values(gid, keyvalues[i])
207	else:
208	codes_set(gid, key, keyvalues[i])
209	i += 1
210
211	codes_write(gid, fout)
212
213	codes_release(gid)
214
215	fin.close()
216	fout.close()
217
218	return
219
220	def copy_dummy_msg(self, filename_in, selectWhere=True,
221	keynames=[], keyvalues=[], filemode='w'):
222	'''Add the content of another input grib file to the objects file but
223	only messages corresponding to keys/values passed to the function.
224	The selectWhere switch decides if to copy the keys equal to (True) or
225	different to (False) the keynames/keyvalues list passed to the function.
226
227	Parameters
228	----------
229	filename_in : :obj:`string`
230	Filename of the input file to read the grib messages from.
231
232	selectWhere : :obj:`boolean`, optional
233	Decides if to copy the keynames and values equal to (True) or
234	different to (False) the keynames/keyvalues list passed to the
235	function. Default is True.
236
237	keynames : :obj:`list` of :obj:`string`, optional
238	List of keynames. Default is an empty list.
239
240	keyvalues : :obj:`list` of :obj:`string`, optional
241	List of keyvalues. Default is an empty list.
242
243	filemode : :obj:`string`, optional
244	Sets the mode for the output file. Default is "w".
245
246	Return
247	------
248
249	'''
250	from eccodes import (codes_grib_new_from_file, codes_is_defined,
251	codes_get, codes_release, codes_write)
252
253	if len(keynames) != len(keyvalues):
254	raise Exception("Give a value for each keyname!")
255
256	fin = open(filename_in, 'rb')
257	fout = open(self.filenames, filemode)
258
259	fields = 0
260
261	while fields < 1:
262	gid = codes_grib_new_from_file(fin)
263
264	if gid is None:
265	break
266
267	select = True
268	i = 0
269	for key in keynames:
270	if not codes_is_defined(gid, key):
271	raise Exception("Key was not defined")
272
273	if selectWhere:
274	select = (select and (str(keyvalues[i]) ==
275	str(codes_get(gid, key))))
276	else:
277	select = (select and (str(keyvalues[i]) !=
278	str(codes_get(gid, key))))
279	i += 1
280
281	if select:
282	fields = fields + 1
283	codes_write(gid, fout)
284
285	codes_release(gid)
286
287	fin.close()
288	fout.close()
289
290	return
291
292	def index(self, index_keys=["mars"], index_file="my.idx"):
293	'''Create index file from a list of files if it does not exist or
294	read an index file.
295
296	Parameters
297	----------
298	index_keys: :obj:`list` of :obj:`string`, optional
299	Contains the list of key parameter names from
300	which the index is to be created.
301	Default is a list with a single entry string "mars".
302
303	index_file: :obj:`string`, optional
304	Filename where the indices are stored.
305	Default is "my.idx".
306
307	Return
308	------
309	iid: :obj:`integer`
310	Grib index id.
311	'''
312	from eccodes import (codes_index_read, codes_index_new_from_file,
313	codes_index_add_file, codes_index_write)
314
315	print("... index will be done")
316	iid = None
317
318	if os.path.exists(index_file):
319	iid = codes_index_read(index_file)
320	print("Use existing index file: %s " % (index_file))
321	else:
322	for filename in self.filenames:
323	print("Inputfile: %s " % (filename))
324	if iid is None:
325	iid = codes_index_new_from_file(filename, index_keys)
326	else:
327	codes_index_add_file(iid, filename)
328
329	if iid is not None:
330	codes_index_write(iid, index_file)
331
332	print('... index done')
333
334	return iid

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