为什么Python CSV模块在运行程序后尝试打开时将CSV文件设为只读？

Question

我正在使用一个程序(如下)来查看两个CSV文件之间某些列的相似性,然后在数据匹配某些规范时创建第三个(两列相同但第三列不相同)以便我可以更新e-邮件列表.

但是,当我在运行程序后尝试打开results.csv文件时,Windows Excel将只以只读模式打开程序.

有什么想法吗？

这是我的代码:

import csv

sample_data = open("sample.csv", "r")
lib_data = open("library.csv", "r")
csv1 = csv.reader(sample_data)
csv2 = csv.reader(lib_data)

results = open("results.csv", "w")
res_csv = csv.writer(results)

limit = 1071
limit2 = 1001

x = 0
y = 0

while (y != limit):
    row1 = csv1.__next__()
    while (x != limit2):
        row2 = csv2.__next__()
        if (row1[0] == row2[3] and row1[1] == row2[2] and row1[2] != row2[5]):
            print ("SAMPLE:")
            print (row1[0], ", ", row1[1], ", ", row1[2])
            print ("LIBRARY:")
            print (row2[3], ", ", row2[2], ", ", row2[5])
            print("\n")
            res_csv.writerow(row1)
        x = x+1
    y = y+1
    x = 0
    lib_data.seek(0)

Answer 1

使用with以确保文件将被正确关闭:

with open("sample.csv", "r") as sample_data:
    with open("library.csv", "r") as lib_data:
        with open("results.csv", "w") as results:
            # other code

with如果你使用的是Python> = 2.7,你甚至可以将几个变量合二为一.