python csv 文件读写

import csv
reader = csv.reader(open("some.csv", "rb"))
for row in reader:
    print row
reader = csv.reader(open("passwd", "rb"), delimiter=':', quoting=csv.QUOTE_NONE)
for row in reader:
    print row
writer = csv.writer(open("some.csv", "wb"))
writer.writerows(someiterable)
csv.register_dialect('unixpwd', delimiter=':', quoting=csv.QUOTE_NONE)
reader = csv.reader(open("passwd", "rb"), 'unixpwd')
filename = "some.csv"
reader = csv.reader(open(filename, "rb"))
try:
    for row in reader:
        print row
except csv.Error, e:
    sys.exit('file %s, line %d: %s' % (filename, reader.line_num, e))
for row in csv.reader(['one,two,three']):
    print row