Question

我有一些我正在处理的代码，但它不再有效。我已经完成了测试，一切都过去了。 writer.write(row)运行。但是当我转到我的sales_report/2017_sales_final.csv时，该文件是空白的。它不显示in_file的值，大小为0kb。我做错了什么？

fieldnames = ['Date', 'Order ID']
in_file = open('sales_report/hardcopy.csv', 'r')
out_file = open('sales_report/2017_sales_final.csv', "w")
reader = csv.DictReader(in_file, fieldnames=fieldnames)
writer = csv.DictWriter(out_file, fieldnames=fieldnames)

for row in reader:
    writer.writerow(row)

writer.writerow({'Your order': '12/15/2017','Order ID': '696969'})

Answer 1

可能，您正在查看该文件，但尚未关闭。通过命令行运行脚本可能会正确显示文件内容，因为当Python退出时，文件句柄将被关闭，但如果在IDE中运行，则句柄可能会保持打开状态。使用with语句确保文件已关闭：

fieldnames = ['Date', 'Order ID']
with open('sales_report/hardcopy.csv', 'r') as in_file:
    with open('sales_report/2017_sales_final.csv', "w") as out_file:
        reader = csv.DictReader(in_file, fieldnames=fieldnames)
        writer = csv.DictWriter(out_file, fieldnames=fieldnames)
        # etc.

# files will be closed outside the with blocks.

Answer 2

You never close the output file.

CSV模块无法写入

2 个答案: