Wrap long lines in Python

Question

How do I wrap long lines in Python without sacrificing indentation    For example    def fun        print   0  Here is a really long sentence with  1   format 3  5    Suppose this goes over the 79 character recommended limit  The way I read it  here is how to indent it   def fun        print   0  Here is a really long   sentence with  1   format 3  5    However  with this approach  the indentation of the continued line matches the indentation of the fun    This looks kinda ugly  If someone was to go through my code  it would look bad to have uneven indentation because of this print statement   How do I indent lines like this effectively without sacrificing code readability

User · Accepted Answer

def fun        print    0  Here is a really long               sentence with  1    format 3  5     Adjacent string literals are concatenated at compile time  just as in C  http   docs python org reference lexical analysis html string-literal-concatenation is a good place to start for more info

User · Answer

You could use the following code where indentation doesn t matter    gt  gt  gt  def fun            return    0  Here is a really long            sentence with  1    format 3  5    You just need to enclose string in the parentheses

User · Answer

You can use the fact that Python concatenates string literals which appear adjacent to each other    gt  gt  gt  def fun            print   0  Here is a really long                    sentence with  1   format 3  5

User · Answer

I m surprised no one mentioned the implicit style above   My preference is to use parens to wrap the string while lining the string lines up visually   Personally I think this looks cleaner and more compact than starting the beginning of the string on a tabbed new line   Note that these parens are not part of a method call      they re only implicit string literal concatenation   Python 2   def fun        print    0  Here is a really               long sentence with  1    format 3  5    Python 3  with parens for print function    def fun        print    0  Here is a really               long sentence with  1    format 3  5     Personally I think it s cleanest to separate concatenating the long string literal from printing it   def fun        s      0  Here is a really             long sentence with  1    format 3  5      print s

User · Answer

I d probably split the long statement up into multiple shorter statements so that the program logic is separated from the definition of the long string    gt  gt  gt  def fun            format string     0  Here is a really long                              sentence with  1           print format string format 3  5    If the string is only just too long and you choose a short variable name then by doing this you might even avoid having to split the string    gt  gt  gt  def fun            s     0  Here is a really long sentence with  1           print s format 3  5

User · Answer

There are two approaches which are not mentioned above  but both of which solve the problem in a way which complies with PEP 8 and allow you to make better use of your space  They are   msg          This message is so long  that it requires        more than  x  lines  sep        and you may want to add more    format          x x  sep 2   n   print msg    Notice how the parentheses are used to allow us not to add plus signs between pure strings  and spread the result over multiple lines without the need for explicit line continuation      ugly and cluttered   The advantages are same with what is described below  the difference is that you can do it anywhere  Compared to the previous alternative  it is visually better when inspecting code  because it outlines the start and end of msg clearly  compare with msg    one every line  which needs one additional thinking step to deduce that those lines add to the same string - and what if you make a typo  forgetting a   on one random line      Regarding this approach  many times we have to build a string using iterations and checks within the iteration body  so adding its pieces within the function call  as shown later  is not an option   A close alternative is   msg    This message is so long  that it requires   msg     many lines to write  one reason for that n  msg     is that it contains numbers  like this   msg     one      str x      which take up more space n  msg     to insert  Note how newlines are also included   msg     and can be better presented in the code itself   print msg    Though the first is preferable   The other approach is like the previous ones  though it starts the message on the  line below the print  The reason for this is to gain space on the left  otherwise the print  itself  pushes  you to the right  This consumption of indentation is the inherited by the rest of the lines comprising the message  because according to PEP 8 they must align with the opening parenthesis of print above them  So if your message was already long  this way it s forced to be spread over even more lines   Contrast   raise TypeError  aaaaaaaaaaaaaaaa                     aaaaaaaaaaaaaaaa                     aaaaaaaaaaaaaaaa     with this  suggested here    raise TypeError       aaaaaaaaaaaaaaaaaaaaaaaa         aaaaaaaaaaaaaaaaaaaaaaaa     The line spread was reduced  Of course this last approach does no apply so much to print  because it is a short call  But it does apply to exceptions   A variation you can have is   raise TypeError        aaaaaaaaaaaaaaaaaaaaaaaa       aaaaaaaaaaaaaaaaaaaaaaaa       aaaaa  x  aaaaa   format x x     Notice how you don t need to have plus signs between pure strings  Also  the indentation guides the reader s eyes  no stray parentheses hanging below to the left  The replacements are very readable  In particular  such an approach makes writing code that generates code or mathematical formulas a very pleasant task

[python] Wrap long lines in Python

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