# HG changeset patch
# User Jeff Hammel <k0scist@gmail.com>
# Date 1412791948 25200
# Node ID 2cadb4349753258ed530918e44d97e9ab1d93609
# Parent  f865bc9165930011bfc70a1b03f537305ae0c3f6
parse by columns

diff -r f865bc916593 -r 2cadb4349753 numerics/read.py
--- a/numerics/read.py	Tue Oct 07 21:04:36 2014 -0700
+++ b/numerics/read.py	Wed Oct 08 11:12:28 2014 -0700
@@ -85,6 +85,7 @@
 
 class CSVParser(argparse.ArgumentParser):
     """CLI option parser"""
+
     def __init__(self, **kwargs):
         kwargs.setdefault('description', __doc__)
         argparse.ArgumentParser.__init__(self, **kwargs)
@@ -92,6 +93,9 @@
                           help="CSV files to read")
         self.add_argument('-+', '--add', dest='added_columns', nargs='+',
                           help="append this column")
+        self.add_argument('-c', '--col', '--columns', dest='columns',
+                          nargs='+', type=int,
+                          help="column numbers to output, starting with 0")
         self.add_argument('-o', '--output', dest='output',
                           type=argparse.FileType('a'), default=sys.stdout,
                           help='output destination, or stdout')
@@ -121,6 +125,10 @@
         for row in data:
             row.extend(options.added_columns)
 
+    if options.columns:
+        rows = [[row[column] for column in options[columns]]
+                for row in rows]
+
     # write CSV
     writer = csv.writer(options.output)
     for row in data: