Format a single value for use in an RFC4180 compliant CSV file. Join multiple of the values returned from this function with a comma to create a row.

csv.py

def _format_csv_value(self, value):
    """Takes a single CSV value string and formats it in compliance with RFC4180.
    Multiple values can be joined together by putting them in a list and using ",".join(the_list).
    http://tools.ietf.org/html/rfc4180#page-3
    
    :param value: A single value destined to be output among multiple in a CSV row
    
    :return: The escaped and/or quoted string if necessary, otherwise simply returns <value>.
    """
    for x in [",", '"', "\n", "\r\n"]:
        if x in value:
            # Must replace double quotes '"' with two double quotes '""'
            value = value.replace('"', '""')
            # and contain all fields in double quotes if they contain commas or double quotes
            value = '"%s"' % value
            break
    return value