Python程序中用csv模塊來操作csv文件的基本使用教程

Title,Release Date,Director
And Now For Something Completely Different,1971,Ian MacNaughton
Monty Python And The Holy Grail,1975,Terry Gilliam and Terry Jones
Monty Python's Life Of Brian,1979,Terry Jones
Monty Python Live At The Hollywood Bowl,1982,Terry Hughes
Monty Python's The Meaning Of Life,1983,Terry Jones

for line in open("samples/sample.csv"):
 title, year, director = line.split(",")
 print year, title

import csv
reader = csv.reader(open("samples/sample.csv"))
for title, year, director in reader:
 print year, title

# File: csv-example-2.py
import csv
class SKV(csv.excel):
 # like excel, but uses semicolons
 delimiter = ";"
 
csv.register_dialect("SKV", SKV)
reader = csv.reader(open("samples/sample.skv"), "SKV")
for title, year, director in reader:
 print year, title

# File: csv-example-3.py
 
import csv
 
reader = csv.reader(open("samples/sample.skv"), delimiter=";")
 
for title, year, director in reader:
 print year, title

# File: csv-example-4.py
 
import csv
import sys
 
data = [
 ("And Now For Something Completely Different", 1971, "Ian MacNaughton"),
 ("Monty Python And The Holy Grail", 1975, "Terry Gilliam, Terry Jones"),
 ("Monty Python's Life Of Brian", 1979, "Terry Jones"),
 ("Monty Python Live At The Hollywood Bowl", 1982, "Terry Hughes"),
 ("Monty Python's The Meaning Of Life", 1983, "Terry Jones")
]
 
writer = csv.writer(sys.stdout)
 
for item in data:
 writer.writerow(item)

import csv


# dialect是訪問csv文件時需要指定的參數(shù)之一，用來確定csv文件的數(shù)據(jù)格式
# 下面這個函數(shù)列舉系統(tǒng)支持的dialect有哪些，默認值是'excel'，用戶也可
# 以從Dialect派生一個類，使用該類的實例作為dialect參數(shù)。
print csv.list_dialects()


def test_writer():
 # csv文件必須以二進制方式open
 with open('eggs.csv', 'wb') as csvfile:
 spamwriter = csv.writer(csvfile)
 spamwriter.writerow(['Spam'] * 5 + ['Baked Beans'])
 spamwriter.writerow(['Spam', 'Lovely Spam', 'Wonderful Spam'])


def test_reader():
 with open('eggs.csv', 'rb') as csvfile:
 spamreader = csv.reader(csvfile)
 for row in spamreader:
 print row


# sniffer 用來推斷csv文件的格式，不是很準(zhǔn)確
def test_sniffer():
 with open('eggs.csv', 'wb') as csvfile:
 spamwriter = csv.writer(csvfile, delimiter=' ')

 spamwriter.writerow(['Spam'] * 2 + ['Baked Beans'])
 spamwriter.writerow(['Spam', 'Lovely Spam', 'Wonderful Spam'])

 # 通常你需要指定與寫入者相同的文件格式才能正確的讀取數(shù)據(jù)
 with open('eggs.csv', 'rb') as csvfile:
 spamreader = csv.reader(csvfile, delimiter=' ')
 for row in spamreader:
 print ', '.join(row)

 # 如果不知道文件格式，sniffer就可以派上用場了
 with open('eggs.csv', 'rb') as csvfile:
 # 用sniffer推斷文件格式，從而得到dialect
 dialect = csv.Sniffer().sniff(csvfile.read(1024))
 print dialect.delimiter, dialect.quotechar

 # 文件重新移動到頭部
 csvfile.seek(0)

 # 用推斷出來的dialect創(chuàng)建reader
 reader = csv.reader(csvfile, dialect)

 for row in reader:
 print ', '.join(row)