将打印输出定向到 .txt 文件 [英] Directing print output to a .txt file

问题描述

有没有办法在python中将所有打印输出保存到txt文件中?假设我的代码中有这两行，我想将打印输出保存到一个名为 output.txt 的文件中.

Is there a way to save all of the print output to a txt file in python? Lets say I have the these two lines in my code and I want to save the print output to a file named output.txt.

print ("Hello stackoverflow!")
print ("I have a question.")

我希望 output.txt 文件包含

Hello stackoverflow!
I have a question.

推荐答案

给 print 一个 file 关键字参数，其中参数的值是一个文件流.我们可以使用 open 函数创建一个文件流:

Give print a file keyword argument, where the value of the argument is a file stream. We can create a file stream using the open function:

print("Hello stackoverflow!", file=open("output.txt", "a"))
print("I have a question.", file=open("output.txt", "a"))

来自关于print的Python文档:

From the Python documentation about print:

file 参数必须是一个带有 write(string) 方法的对象；如果它不存在或 None，将使用 sys.stdout.

The file argument must be an object with a write(string) method; if it is not present or None, sys.stdout will be used.

和 open 的文档:

And the documentation for open:

打开file并返回一个对应的文件对象.如果无法打开文件，则会引发 OSError.

Open file and return a corresponding file object. If the file cannot be opened, an OSError is raised.

"a" 作为 open 的第二个参数的意思是追加"；- 换句话说，文件的现有内容不会被覆盖.如果您希望文件被覆盖，请使用 "w".

The "a" as the second argument of open means "append" - in other words, the existing contents of the file won't be overwritten. If you want the file to be overwritten instead, use "w".

多次使用 open 打开文件对于性能来说并不理想.理想情况下，您应该打开它并为其命名，然后将该变量传递给 print 的 file 选项.您必须记住之后关闭文件！

Opening a file with open many times isn't ideal for performance, however. You should ideally open it once and name it, then pass that variable to print's file option. You must remember to close the file afterwards!

f = open("output.txt", "a")
print("Hello stackoverflow!", file=f)
print("I have a question.", file=f)
f.close()

对此还有一个语法快捷方式，即 with 块.这将在块的末尾为您关闭您的文件:

There's also a syntactic shortcut for this, which is the with block. This will close your file at the end of the block for you:

with open("output.txt", "a") as f:
    print("Hello stackoverflow!", file=f)
    print("I have a question.", file=f)

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