How do I specify new lines in a string in order to write multiple lines to a file?

Question

How can I indicate a newline in a string in Python, so that I can write multiple lines to a text file?

Answer 1

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.

Answer 2

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

If you use Python 2, you do not use the parentheses on the print function.

Answer 3

Platform-independent line breaker: Linux, Windows, and iOS

import os
keyword = 'physical'+ os.linesep + 'distancing'
print(keyword)

Output:

physical
distancing

Answer 4

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

Answer 5

Here is a more readable solution that will work correctly even if you aren't at top level indentation (e.g., in a function definition).

import textwrap
file.write(textwrap.dedent("""
    Life's but a walking shadow, a poor player
    That struts and frets his hour upon the stage
    And then is heard no more: it is a tale
    Told by an idiot, full of sound and fury,
    Signifying nothing.
"""))

Answer 6

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()

Answer 7

In Python you can just use the new-line character, i.e. \n

Answer 8

As mentioned in other answers: "The new line character is \n. It is used inside a string".

I found the most simple and readable way is to use the "format" function, using nl as the name for a new line, and break the string you want to print to the exact format you going to print it:

Python 2:

print("line1{nl}"
      "line2{nl}"
      "line3".format(nl="\n"))

Python 3:

nl = "\n"
print(f"line1{nl}"
      f"line2{nl}"
      f"line3")

That will output:

line1
line2
line3

This way it performs the task, and also gives high readability of the code :)

Answer 9

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.

Answer 10

It is worth noting that when you inspect a string using the interactive Python shell or a Jupyter Notebook, the \n and other backslashed strings like \t are rendered literally:

>>> gotcha = 'Here is some random message...'
>>> gotcha += '\nAdditional content:\n\t{}'.format('Yet even more great stuff!')
>>> gotcha
'Here is some random message...\nAdditional content:\n\tYet even more great stuff!'

The newlines, tabs, and other special non-printed characters are rendered as whitespace only when printed, or written to a file:

>>> print('{}'.format(gotcha))
Here is some random message...
Additional content:
    Yet even more great stuff!

Answer 11

Most escape characters in string literals from Java are also valid in Python, such as "\r" and "\n".

Answer 12

\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.....

Answer 13

In Python 3, the language takes care of encoding newlines for you in the platform's native representation. That means \r\n on Windows, and just \n on grown-up systems.

Even on U*x systems, reading a file with Windows line endings in text mode returns correct results for text, i.e. any \r characters before the \n characters are silently dropped.

If you need total control over the bytes in the file, you can use binary mode. Then every byte corresponds exactly to one byte, and Python performs no translation.

>>> # Write a file with different line endings, using binary mode for full control
>>> with open('/tmp/demo.txt', 'wb') as wf:
...     wf.write(b'DOS line\r\n')
...     wf.write(b'U*x line\n')
...     wf.write(b'no line')
10
9
7

>>> # Read the file as text
>>> with open('/tmp/demo.txt', 'r') as text:
...     for line in text:
...         print(line, end='')
DOS line
U*x line
no line

>>> # Or more demonstrably
>>> with open('/tmp/demo.txt', 'r') as text:
...     for line in text:
...         print(repr(line))
'DOS line\n'
'U*x line\n'
'no line'

>>> # Back to bytes!
>>> with open('/tmp/demo.txt', 'rb') as binary:
...     for line in binary:
...         print(line)
b'DOS line\r\n'
b'U*x line\n'
b'no line'

>>> # Open in binary, but convert back to text
>>> with open('/tmp/demo.txt', 'rb') as binary:
...     for line in binary:
...         print(line.decode('utf-8'), end='')
DOS line
U*x line
no line

>>> # Or again in more detail, with repr()
>>> with open('/tmp/demo.txt', 'rb') as binary:
...     for line in binary:
...         print(repr(line.decode('utf-8')))
'DOS line\r\n'
'U*x line\n'
'no line'

Answer 14

Use:

"{}\n{}\n{}".format(
    "line1",
    "line2",
    "line3"
)

I personally prefer this format.

Answer 15

\n separates the lines of a string. In the following example, I keep writing the records in a loop. Each record is separated by \n.

f = open("jsonFile.txt", "w")

for row_index in range(2, sheet.nrows):

  mydict1 = {
    "PowerMeterId" : row_index + 1,
    "Service": "Electricity",
    "Building": "JTC FoodHub",
    "Floor": str(Floor),
    "Location": Location,
    "ReportType": "Electricity",
    "System": System,
    "SubSystem": "",
    "Incomer": "",
    "Category": "",
    "DisplayName": DisplayName,
    "Description": Description,
    "Tag": tag,
    "IsActive": 1,
    "DataProviderType": int(0),
    "DataTable": ""
  }
  mydict1.pop("_id", None)
  f.write(str(mydict1) + '\n')

f.close()

Answer 16

Various equivalent methods

Using print

print already appends a newline by default!

with open("out.txt", "w") as f:
    print("First", file=f)
    print("Second", file=f)

Equivalently:

with open("out.txt", "w") as f:
    print("First\nSecond", file=f)

To print without automatically adding a newline, use sep="" (since sep="\n" is the default):

with open("out.txt", "w") as f:
    print("First\nSecond\n", sep="", file=f)

---

Using f.write

For files opened in text mode:

with open("out.txt", "w") as f:
    f.write("First\nSecond\n")

For files opened in binary mode, the files will be written without automatic translation of \n to the platform-specific line terminator. To enforce the newline character for the current platform is used, use os.linesep instead of \n:

with open("out.txt", "wb") as f:
    f.write("First" + os.linesep)
    f.write("Second" + os.linesep)

---

Output file

Visually:

First
Second

On Linux, the newlines will be separated by \n:

First\nSecond\n

On Windows, the newlines will be separated by \r\n:

First\r\nSecond\r\n

To avoid automatic translation of \n to \r\n for files opened in text mode, open the file using open("out.txt", "w", newline="\n").