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source: flex_extract.git/source/python/classes/GribUtil.py @ 79729d5

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Last change on this file since 79729d5 was 79729d5, checked in by Anne Philipp <anne.philipp@…>, 5 years ago
switched from python2 to python3
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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	import os
46
47	from eccodes import (codes_grib_new_from_file, codes_is_defined, codes_get,
48	codes_release, codes_set, codes_write, codes_index_read,
49	codes_index_new_from_file, codes_index_add_file,
50	codes_index_write, codes_set_values)
51
52	# ------------------------------------------------------------------------------
53	# CLASS
54	# ------------------------------------------------------------------------------
55	class GribUtil(object):
56	'''
57	Class for GRIB utilities (new methods) based on GRIB API
58	'''
59	# --------------------------------------------------------------------------
60	# CLASS FUNCTIONS
61	# --------------------------------------------------------------------------
62	def __init__(self, filenames):
63	'''Initialise an object of GribUtil and assign a list of filenames.
64
65	Parameters
66	----------
67	filenames : :obj:`list` of :obj:`strings`
68	A list of filenames.
69
70	Return
71	------
72
73	'''
74
75	self.filenames = filenames
76
77	return
78
79
80	def get_keys(self, keynames, wherekeynames=[], wherekeyvalues=[]):
81	'''Get keyvalues for a given list of keynames a where statement
82	can be given (list of key and list of values)
83
84	Parameters
85	----------
86	keynames : :obj:`list` of :obj:`string`
87	List of keynames.
88
89	wherekeynames : :obj:`list` of :obj:`string`, optional
90	Default value is an empty list.
91
92	wherekeyvalues : :obj:`list` of :obj:`string`, optional
93	Default value is an empty list.
94
95	Return
96	------
97	return_list : :obj:`list` of :obj:`string`
98	List of keyvalues for given keynames.
99	'''
100
101	fileid = open(self.filenames, 'r')
102
103	return_list = []
104
105	while 1:
106	gid = codes_new_from_file(fileid)
107
108	if gid is None:
109	break
110
111	if len(wherekeynames) != len(wherekeyvalues):
112	raise Exception("Number of key values and key names must be \
113	the same. Give a value for each keyname!")
114
115	select = True
116	i = 0
117	for wherekey in wherekeynames:
118	if not codes_is_defined(gid, wherekey):
119	raise Exception("where key was not defined")
120
121	select = (select and (str(wherekeyvalues[i]) ==
122	str(codes_get(gid, wherekey))))
123	i += 1
124
125	if select:
126	llist = []
127	for key in keynames:
128	llist.extend([str(codes_get(gid, key))])
129	return_list.append(llist)
130
131	codes_release(gid)
132
133	fileid.close()
134
135	return return_list
136
137
138	def set_keys(self, fromfile, keynames, keyvalues, wherekeynames=[],
139	wherekeyvalues=[], strict=False, filemode='w'):
140	'''Opens the file to read the grib messages and then write
141	the selected messages (with wherekeys) to a new output file.
142	Also, the keyvalues of the passed list of keynames are set.
143
144	Parameters
145	----------
146	fromfile : :obj:`string`
147	Filename of the input file to read the grib messages from.
148
149	keynames : :obj:`list` of :obj:`string`
150	List of keynames to set in the selected messages.
151	Default is an empty list.
152
153	keyvalues : :obj:`list` of :obj:`string`
154	List of keyvalues to set in the selected messages.
155	Default is an empty list.
156
157	wherekeynames : :obj:`list` of :obj:`string`, optional
158	List of keynames to select correct message.
159	Default value is an empty list.
160
161	wherekeyvalues : :obj:`list` of :obj:`string`, optional
162	List of keyvalues for keynames to select correct message.
163	Default value is an empty list.
164
165	strict : :obj:`boolean`, optional
166	Decides if everything from keynames and keyvalues
167	is written out the grib file (False) or only those
168	meeting the where statement (True). Default is False.
169
170	filemode : :obj:`string`, optional
171	Sets the mode for the output file. Default is "w".
172
173	Return
174	------
175
176	'''
177	if len(wherekeynames) != len(wherekeyvalues):
178	raise Exception("Give a value for each keyname!")
179
180	fout = open(self.filenames, filemode)
181	fin = open(fromfile)
182
183	while 1:
184	gid = codes_grib_new_from_file(fin)
185
186	if gid is None:
187	break
188
189	select = True
190	i = 0
191	for wherekey in wherekeynames:
192	if not codes_is_defined(gid, wherekey):
193	raise Exception("wherekey was not defined")
194
195	select = (select and (str(wherekeyvalues[i]) ==
196	str(codes_get(gid, wherekey))))
197	i += 1
198
199	if select:
200	i = 0
201	for key in keynames:
202	if key == 'values':
203	codes_set_values(gid, keyvalues[i])
204	else:
205	codes_set(gid, key, keyvalues[i])
206	i += 1
207
208	codes_write(gid, fout)
209
210	codes_release(gid)
211
212	fin.close()
213	fout.close()
214
215	return
216
217	def copy_dummy_msg(self, filename_in, selectWhere=True,
218	keynames=[], keyvalues=[], filemode='w'):
219	'''Add the content of another input grib file to the objects file but
220	only messages corresponding to keys/values passed to the function.
221	The selectWhere switch decides if to copy the keys equal to (True) or
222	different to (False) the keynames/keyvalues list passed to the function.
223
224	Parameters
225	----------
226	filename_in : :obj:`string`
227	Filename of the input file to read the grib messages from.
228
229	selectWhere : :obj:`boolean`, optional
230	Decides if to copy the keynames and values equal to (True) or
231	different to (False) the keynames/keyvalues list passed to the
232	function. Default is True.
233
234	keynames : :obj:`list` of :obj:`string`, optional
235	List of keynames. Default is an empty list.
236
237	keyvalues : :obj:`list` of :obj:`string`, optional
238	List of keyvalues. Default is an empty list.
239
240	filemode : :obj:`string`, optional
241	Sets the mode for the output file. Default is "w".
242
243	Return
244	------
245
246	'''
247	if len(keynames) != len(keyvalues):
248	raise Exception("Give a value for each keyname!")
249
250	fin = open(filename_in)
251	fout = open(self.filenames, filemode)
252
253	fields = 0
254
255	while fields < 1:
256	gid = codes_grib_new_from_file(fin)
257
258	if gid is None:
259	break
260
261	select = True
262	i = 0
263	for key in keynames:
264	if not codes_is_defined(gid, key):
265	raise Exception("Key was not defined")
266
267	if selectWhere:
268	select = (select and (str(keyvalues[i]) ==
269	str(codes_get(gid, key))))
270	else:
271	select = (select and (str(keyvalues[i]) !=
272	str(codes_get(gid, key))))
273	i += 1
274
275	if select:
276	fields = fields + 1
277	codes_write(gid, fout)
278
279	codes_release(gid)
280
281	fin.close()
282	fout.close()
283
284	return
285
286	def index(self, index_keys=["mars"], index_file="my.idx"):
287	'''Create index file from a list of files if it does not exist or
288	read an index file.
289
290	Parameters
291	----------
292	index_keys: :obj:`list` of :obj:`string`, optional
293	Contains the list of key parameter names from
294	which the index is to be created.
295	Default is a list with a single entry string "mars".
296
297	index_file: :obj:`string`, optional
298	Filename where the indices are stored.
299	Default is "my.idx".
300
301	Return
302	------
303	iid: :obj:`integer`
304	Grib index id.
305	'''
306	print("... index will be done")
307	iid = None
308
309	if os.path.exists(index_file):
310	iid = codes_index_read(index_file)
311	print("Use existing index file: %s " % (index_file))
312	else:
313	for filename in self.filenames:
314	print("Inputfile: %s " % (filename))
315	if iid is None:
316	iid = codes_index_new_from_file(filename, index_keys)
317	else:
318	codes_index_add_file(iid, filename)
319
320	if iid is not None:
321	codes_index_write(iid, index_file)
322
323	print('... index done')
324
325	return iid

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