How does Python's triple-quote string work?

Question

How should this function be changed to return "123456"?

def f():
    s = """123
    456"""
    return s

UPDATE: Everyone, the question is about understanding how to not have \t or whatever when having a multiline comment, not how to use the re module.

This is not homework. I'm trying to understand how `"""` works. — Ram Rachum, Oct 05 '09 at 15:10
@cool-RR: and how are we supposed to know that you have `\t` in it? — SilentGhost, Oct 05 '09 at 15:23
@cool-RR: By not adding the tab in the beginning of the row. When asking questions, you really need to explain what the problem is, not the question that is on top of your head. — Lennart Regebro, Oct 05 '09 at 16:02
@SilentGhost: I guess a person who understands how Python works with `"""` will see immediately that my string would contain a `\t` (or spaces, which are equivalent for this matter) — Ram Rachum, Oct 05 '09 at 22:05

score 54 · Accepted Answer · answered Oct 05 '09 at 17:46

54

Don't use a triple-quoted string when you don't want extra whitespace, tabs and newlines.

Use implicit continuation, it's more elegant:

def f():
    s = ('123'
         '456')
    return s

answered Oct 05 '09 at 17:46

nosklo

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1

This used to come naturally to me but not when I had to plug in variable values using a ex:%s , but alas, even the following works: `s = ('String %s '` `'String %s') %('foo', 'bar')` – Spade Dec 15 '14 at 08:41

score 18 · Answer 2 · answered Oct 05 '09 at 15:12

18

def f():
  s = """123\
456"""
  return s

Don't indent any of the blockquote lines after the first line; end every line except the last with a backslash.

answered Oct 05 '09 at 15:12

Slumberheart

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+1: even though I do not like bashslashes: could use replace('\n','') – van Oct 05 '09 at 17:52
... and not {{{return s.replace('\n', '')}}}, but rather in the assignment itself: {{{456""".replace('\n', '')}}} – van Oct 05 '09 at 17:56

score 15 · Answer 3 · answered Oct 05 '09 at 16:47

15

Subsequent strings are concatenated, so you can use:

def f():
    s = ("123"
         "456")
    return s

This will allow you to keep indention as you like.

answered Oct 05 '09 at 16:47

Denis Otkidach

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Note to OP - no comma between "123" and "456". The ()'s are there to avoid having to use '\' for line continuations. – PaulMcG Oct 05 '09 at 19:19

score 11 · Answer 4 · answered May 26 '11 at 03:50

11

textwrap.dedent("""\
                123
                456""")

From the standard library. First "\" is necessary because this function works by removing the common leading whitespace.

answered May 26 '11 at 03:50

claudelepoisson

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Does not answer the question, but does answer Google query! Actually asked at: http://stackoverflow.com/questions/1412374/python-triple-quote-multi-line-indentation – Ciro Santilli OurBigBook.com Jan 26 '17 at 09:45

score 7 · Answer 5 · answered Oct 05 '09 at 14:52

7

Maybe I'm missing something obvious but what about this:

def f():
    s = """123456"""
    return s

or simply this:

def f():
    s = "123456"
    return s

or even simpler:

def f():
    return "123456"

If that doesn't answer your question, then please clarify what the question is about.

answered Oct 05 '09 at 14:52

Joachim Sauer

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About understanding how to not have \t or whatever when have a multiline comment. – Ram Rachum Oct 05 '09 at 15:11
9

A triple quoted string isn't a multiline comment, it's a raw string, and contains exactly what you type into it. – JimB Oct 05 '09 at 15:20
3

Technically a triple-quoted string is not a raw string, as backslash escapes are still interpreted. It is a normal python string in which unescaped newlines are retained (instead of causing a parse error). You can make a truly raw triple-quoted string with r"""blabla""". This is useful for making regex patterns which need to contain both single and double quotes and backslashes. – pix Oct 10 '14 at 04:03

score 0 · Answer 6 · edited Jun 20 '20 at 09:12

You might want to check this str.splitlines([keepends])

Return a list of the lines in the string, breaking at line boundaries. This method uses the universal newlines approach to splitting lines. Line breaks are not included in the resulting list unless keepends is given and true.

Python recognizes "\r", "\n", and "\r\n" as line boundaries for 8-bit strings.

So, for the problem at hand ... we could do somehting like this..

>>> s = """123
... 456"""
>>> s
'123\n456'
>>> ''.join(s.splitlines())
'123456'

score -1 · Answer 7 · answered Oct 05 '09 at 14:53

-1

re.sub('\D+', '', s)

will return a string, if you want an integer, convert this string with int.

answered Oct 05 '09 at 14:53

SilentGhost

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score -1 · Answer 8 · answered Oct 05 '09 at 14:53

-1

Try

import re

and then

    return re.sub("\s+", "", s)

answered Oct 05 '09 at 14:53

Aaron Digulla

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Juparave · Answer 9 · 2009-10-05T18:41:06.640

-3

My guess is:

def f():
    s = """123
    456"""
    return u'123456'

Minimum change and does what is asked for.

edited Oct 05 '09 at 18:41

answered Oct 05 '09 at 14:59

Juparave

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Was probably downvoted because the function was supposed to return a string. – recursive Oct 05 '09 at 17:28
You're right, it probably has to return a string and I returned an integer, anyway I don't get the downvoted thing either, I'm new to python – Juparave Oct 05 '09 at 17:47
so change the last line to return "123456" – foosion Oct 05 '09 at 18:12
Now that I re-read the question I know why my answer was downvoted, the question is referring to 'How does Python’s triple-quote string work?' an my answer doesn't comment anything about it – Juparave Oct 05 '09 at 18:43

How does Python's triple-quote string work?

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