Module CSV

source code

Reading/writing of comma-separated value strings/files. An enhanced interface to the Python standard library csv module, and supports its dialect system to alter the expected standard CSV format, e.g. delimiters.

Usage

Import as:

   import wsatools.CSV as csv

Read/Write CSV Files

To write the results of a database query to a CSV file:

   results = db.query("sourceID, ra, dec", "lasSource")
   csv.File("sources.csv", 'w').writelines(results)

To read a file using the standard dialect:

   for sourceID, Ra, Dec in csv.File("sources.csv"):
       if float(Dec) > 0.0:
           print sourceID
           break

To alter the dialect based on the contents of a file:

   csv.File.autoSetDialect("strange.csv")
   rows = csv.File("strange.csv").readlines()

To manually change the dialect to, say, make the delimiter a single colon character, and to ignore comment lines that start with a double-hyphen:

   from csv import excel
   class ColonDialect(excel):
       delimiter = ':'
   csv.File.setDialect(ColonDialect)
   csv.File.commentMarker = '--'
   rows = csv.File("coloned.csv").readlines()

Convert between sequences and CSV strings

To convert a CSV string to a list:

   elements = list(csv.values('1.0, 2.0, 3.0'))

To convert a list to a CSV string:

   print csv.join([1.0, 2.0, 3.0])

To change dialects:

   import csv as pycsv
   pycsv.register_dialect('strange', csv.sniffDialect('strange.csv'))
   elements = list(csv.values('1.0-2.0-3.0', dialect='strange'))

or:

   pycsv.register_dialect('colon', ColonDialect)
   elements = list(csv.values('1.0:2.0:3.0', dialect='colon'))