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comparison numerics/cat_columns.py @ 62:18c0820bfe12

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stub concatenating columns
author Jeff Hammel <k0scist@gmail.com>
date Mon, 23 Feb 2015 10:50:13 -0800
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61:82a18c9337c3 62:18c0820bfe12
1 #!/usr/bin/env python
2 # -*- coding: utf-8 -*-
3
4 """
5 output columns of various CSV files
6
7 Example::
8
9 > cat-columns foo.csv:0 bar.csv:1,2,3 fleem.csv
10
11 This will generate CSV output with the first column from `foo.csv`,
12 the 2nd, 3rd, and 4th columns from `bar.csv`,
13 and all columns from `fleem.csv`.
14 """
15
16 # imports
17 import argparse
18 import csv
19 import os
20 import sys
21 import time
22 from collections import OrderedDict
23 from .read import read_csv
24
25 # module globals
26 __all__ = ['cat_columns', 'CatColumnParser', 'main']
27
28 def cat_columns(csv_files):
29 """
30 csv_files -- an iterable of 2-tuples of `path`, columns
31 """
32
33 rows = []
34
35 class CatColumnParser(argparse.ArgumentParser):
36 """CLI option parser"""
37 def __init__(self, **kwargs):
38 kwargs.setdefault('formatter_class', argparse.RawTextHelpFormatter)
39 kwargs.setdefault('description', __doc__)
40 argparse.ArgumentParser.__init__(self, **kwargs)
41 self.add_argument('csv', nargs='+',
42 help="path to CSV files and columns to output, delimited by ':' and comma-separated")
43 self.add_argument('-o', '--output', dest='output',
44 type=argparse.FileType('a'), default=sys.stdout,
45 help="where to output to, or stdout by default")
46 self.options = None
47
48 def parse_args(self, *args, **kw):
49 options = argparse.ArgumentParser.parse_args(self, *args, **kw)
50 self.validate(options)
51 self.options = options
52 return options
53
54 def validate(self, options):
55 """validate options"""
56
57 def main(args=sys.argv[1:]):
58 """CLI"""
59
60 # parse command line options
61 parser = CatColumnParser()
62 options = parser.parse_args(args)
63
64 # get the data
65 csv_files = OrderedDict()
66 missing = []
67 for item in options.csv:
68 if ':' in item:
69 path, columns = item.rsplit(':', 1)
70 columns = columns.strip()
71 if columns:
72 columns = [int(column) for column in columns.split(',')]
73 else:
74 columns = None
75 else:
76 path = item
77 columns = None
78 if not os.path.exists(path):
79 missing.append(path)
80 if missing:
81 parser.error("File(s) not found:\n{}".format('\n'.join(missing)))
82
83 # concatenate the rows
84 data = cat_columns(csv_files.items())
85
86 # output it
87 writer = csv.writer(options.output)
88 for row in data:
89 writer.write_row(row)
90 options.output.flush()
91
92 if __name__ == '__main__':
93 main()
94
95