如何使 Python 中的 file.write() 方法显式写入换行符？

Question

I am trying to write text to an output file that explicitly shows all of the newline characters ( \n , \r , \r\n ,). I am using Python 3 and Windows 7. My thought was to do this by converting the strings that I am writing into bytes.

My code looks like this:

file_object = open(r'C:\Users\me\output.txt', 'wb')`
for line in lines:
    line = bytes(line, 'UTF-8')  
    print('Line: ', line)   #for debugging
    file_object.write(line)
file_object.close()

The print( ) statement to standard output (my Windows terminal) is as I want it to be. For example, one line looks like so, with the \n character visible.

Line: b'<p class="byline">Foo C. Bar</p>\n'

However, the write() method does not explicitly print any of the newline characters in my output.txt file. Why does write() not explicitly show the newline characters in my output text file, even though I'm writing in bytes mode, but print does explicitly show the newline characters in the windows terminal?

Answer 1

What Python does when writing strings or bytes to text or binary files:

• Strings to a text file. Directly written.
• Bytes to a text file. Writes the repr .
• Strings to a binary file. Throws an exception.
• Bytes to a binary file. Directly written.

You say that you get what you're looking for when you write a bytes to standard out (a text file). That, with the pseudo-table above, suggests you might look into using repr . Specifically, if you're looking for the output b'<p class="byline">Foo C. Bar</p>\n' , you're looking for the repr of a bytes object. If line was a str to start with and you don't actually need that b at the beginning, you might instead be looking for the repr of the string, '<p class="byline">Foo C. Bar</p>\n' . If so, you could write it like this:

with open(r'C:\Users\me\output.txt', 'w') as file_object:
    for line in lines:
        file_object.write(repr(line) + '\n')