Is there any simple way to add \n in r'' string in python

Question

I need to add several paths into a single line string with a \n character at the end. For convenience, The key word r is added at the front of the string. In this case the character '\n' couldn't be display normally.

Ex.

str_output = r'name = %(name)s, some_dir = \\folder0\\..., description = "%(des)s\n'
print(str_output % {'name':'new', 'des':'new add one'})

The out put will display without line break. Currently I use string plus to by pass this problem. Such as:

str_output = r'name = %(name)s, some_dir = \\folder0\\..., description = "%(des)s' + '\n'

Instead of the previous define of str_output. I'm curious about is there any other convenience way to do this? The string plus looks ugly in my codes. Thank you!

Answer 1

I'm a little late to the party here but this was a recent requirement for myself. I wanted a multiline axis label with LaTeX parsing for a 2-dimensional histogram in matplotlib.

My solution was to use parentheses to start line continuation, and then combine normal and raw strings to achieve the line break:

xlabel=('Time of Flight (ToF)\n'
        r'[$\times10^3$ arb. units]')

Here’s how this looks:

This can be extended to more complex strings.

Answer 2

The r you're putting before the start of your string literal indicates to Python that is is a "raw" string, and that escape sequences within it should be treated as regular characters. I suspect you're doing this because of the doubled backslash characters you have, which you don't want python to interpret as a single escaped backslash character. However, the raw literal is also preventing \n from being interpreted as a newline character.

The only fixes are to keep the the raw string literal separate from the newline, then join them (like you are already doing), or to use a regular string literal and escape your backslashes:

str_output = 'name = %(name)s, some_dir = \\\\folder0\\\\..., description = "%(des)s\n'

Answer 3

The string literal prefix r signifies a raw string, that is escape's are regular characters. If you really want to use raw strings, you can try something like:

name = 'new'
des = 'new add one'
newline = '\n'
str_output = rf'name = {name}s, some_dir = \\folder0\\..., description = "{des}s{newline}s'
print(str_output)

Although this means that you'll have to bear the newline in every dict.

Another way of doing it which has a little more meaning:

str_output = r'name = %(name)s, some_dir = \\folder0\\..., description = "%(des)s%(\n)s'
print(str_output % {'name':'new', 'des':'new add one', '\\n': '\n'})

Answer 4

As already noted in this answer, use parentheses to combine raw strings and ordinary strings by implicit concatenation of string literals. Using also formatted string literals, which are available in Python >= 3.6, the result is:

name = 'some_name'
des = 'some decription'
message = (rf'{name = !s}s, some_dir = \folder0\..., description = {des}s' '\n')
print(message)