In comparison to Java (in a String), you would do something like "First Line\r\nSecond Line".
So how would you do that in Python, for purposes of writing multiple lines on a regular file?
It depends on how correct you want to be. \n will usually do the job. If you really want to get it right, you look up the newline character in the os package. (It's actually called linesep.)
Note: when writing to files using the Python API, do not use the os.linesep. Just use \n; Python automatically translates that to the proper newline character for your platform.
The new line character is \n. It is used inside a string.
Example:
print 'First line \n Second line'
where \n is the newline character.
This would yield the result:
First line
Second line
You can either write in the new lines separately or within a single string, which is easier.
Example 1
Input
line1 = "hello how are you"
line2 = "I am testing the new line escape sequence"
line3 = "this seems to work"
You can write the '\n' separately:
file.write(line1)
file.write("\n")
file.write(line2)
file.write("\n")
file.write(line3)
file.write("\n")
Output
hello how are you
I am testing the new line escape sequence
this seems to work
Example 2
Input
As others have pointed out in the previous answers, place the \n at the relevant points in your string:
line = "hello how are you\nI am testing the new line escape sequence\nthis seems to work"
file.write(line)
Output
hello how are you
I am testing the new line escape sequence
this seems to work
In Python you can just use the new-line character, i.e. \n
If you are entering several lines of text at once, I find this to be the most readable format.
file.write("\
Life's but a walking shadow, a poor player\n\
That struts and frets his hour upon the stage\n\
And then is heard no more: it is a tale\n\
Told by an idiot, full of sound and fury,\n\
Signifying nothing.\n\
")
The \ at the end of each line escapes the new line (which would cause an error).
Simplest solution
If you only call print without any arguments, it will output a blank line.
print
You can pipe the output to a file like this (considering your example):
f = open('out.txt', 'w')
print 'First line' >> f
print >> f
print 'Second line' >> f
f.close()
Not only is it OS-agnostic (without even having to use the os package), it's also more readable than putting \n within strings.
Explanation
The print() function has an optional keyword argument for the end of the string, called end, which defaults to the OS's newline character, for eg. \n. So, when you're calling print('hello'), Python is actually printing 'hello' + '\n'. Which means that when you're calling just print without any arguments, it's actually printing '' + '\n', which results in a newline.
Alternative
Use multi-line strings.
s = """First line
Second line
Third line"""
f = open('out.txt', 'w')
print s >> f
f.close()
The same way with '\n', though you'd probably not need the '\r'. Is there a reason you have it in your Java version? If you do need/want it, you can use it in the same way in Python too.
\n - simple newline character insertion works :
# Here's the test example - string with newline char :
In [36]: test_line = "Hi!!!\n testing first line.. \n testing second line.. \n and third line....."
# Output:
In [37]: print(test_line)
Hi!!!
testing first line..
testing second line..
and third line.....
Most escape characters in string literals from Java are also valid in Python, such as "\r", "\n"
来源：https://stackoverflow.com/questions/11497376/how-do-i-specify-new-lines-on-python-when-writing-on-files