python3 - 打印我刚刚写入的文件

Question

这个问题已经有答案了:

Python write to a file returns empty file (2 个回答)

已关闭 4 年前。

这是《艰难学习Python》练习中的一个问题。练习是将一个文件复制到另一个文件，我工作得很好，但我想稍微扩展代码以打印刚刚写入的文件。这是代码:

from sys import argv
from os.path import exists

script, from_file, to_file = argv

print(f"Copying from {from_file} to {to_file}")

#creates a variable called "in_file" from the argv "from_file", opens it and reads it.
in_file = open(from_file).read()
print(f"The contents of 'from_file' is:\n {in_file}")

print(f"The input file is {len(in_file)} bytes long")
print(f"Does the output file exist? {exists(to_file)}")
print(f"Ready, hit RETURN to contiune, CTRC-C to abort")
input(">")

#creates variable "out_file" and opens the "to file" argv 'w' means writable
out_file = open(to_file, 'w')

#writes data from "in_file to "out_file"
out_file.write(in_file)

print("Alright, all done")

#Try to print the file we wrote to
blah = open(to_file).read()
print(f"We printed: {blah}")

当我运行此脚本时，会发生以下情况:

$ python3 ex17.py test.text new_file.text
Copying from test.text to new_file.text
The contents of 'from_file' is:
 This is a test file.

The input file is 21 bytes long
Does the output file exist? True
Ready, hit RETURN to contiune, CTRC-C to abort
>
Alright, all done
We printed:

所以我的问题是没有打印任何内容。如果我发现“new_file.text”，内容是正确的，但代码显然有问题，因为它根本没有打印它。

有什么建议吗？

Answer 1

我刚刚测试过。这是因为 out_file 没有关闭。在out_file.write(in_file)中添加out_file.close()后，当然建议您使用with而不是打开文件。