python · dancinglightning · Aug 24, 2021 · Aug 24, 2021 · Aug 24, 2021 · Aug 25, 2021
diff --git a/Doc/tutorial/introduction.rst b/Doc/tutorial/introduction.rst
@@ -182,6 +182,29 @@ the first quote::
   >>> print(r'C:\some\name')  # note the r before the quote
   C:\some\name

+There is one subtle aspect to raw strings that is of special concern to Windows
+programmers:  a raw string may not end in an odd number of ``\`` characters.
+This is because the interpreter sees this as an escaped quote character, and so
+it does not recognize it as the end of the string::
+
+   >>> fn = r'C:\this\will\not\work\'
+     File "<stdin>", line 1
+       fn = r'C:\this\will\not\work\'
+                                    ^
+   SyntaxError: EOL while scanning string literal
+
+There are several workarounds for this.  One is to use regular strings and
+double the backslashes::
+
+   >>> fn = 'C:\\this\\will\\work\\'
+
+Another is to add a blank character before the quote and then remove it::
+
+   >>> fn = r'C:\this\will\work\ '.strip()
+
+Strings can be concatenated (glued together) with the ``+`` operator, and
+ repeated with ``*``::
+
 String literals can span multiple lines.  One way is using triple-quotes:
 ``"""..."""`` or ``'''...'''``.  End of lines are automatically
 included in the string, but it's possible to prevent this by adding a ``\`` at

diff --git a/Misc/NEWS.d/next/Documentation/2021-08-26-16-53-22.bpo-11479.zHAOnZ.rst b/Misc/NEWS.d/next/Documentation/2021-08-26-16-53-22.bpo-11479.zHAOnZ.rst
@@ -0,0 +1 @@
+Added a discussion of trailing backslash in raw string to tutorial
-Original file line number
+Diff line change
@@ -182,6 +182,29 @@ the first quote::
        >>> print(r'C:\some\name')  # note the r before the quote
        C:\some\name
+    There is one subtle aspect to raw strings that is of special concern to Windows
+    programmers:  a raw string may not end in an odd number of ``\`` characters.
+    This is because the interpreter sees this as an escaped quote character, and so
+    it does not recognize it as the end of the string::
+       >>> fn = r'C:\this\will\not\work\'
+         File "<stdin>", line 1
+           fn = r'C:\this\will\not\work\'
+                                        ^
+       SyntaxError: EOL while scanning string literal
+    There are several workarounds for this.  One is to use regular strings and
+    double the backslashes::
+       >>> fn = 'C:\\this\\will\\work\\'
+    Another is to add a blank character before the quote and then remove it::
+       >>> fn = r'C:\this\will\work\ '.strip()
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            Julian
  

      

      

      


        Aug 25, 2021



      
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      Personally I wouldn't mention this one -- it adds a runtime cost if it's inside some loop or function call, which on its own isn't a huge deal, but it also means you get unexpected behavior if you don't fully realize what this does and try it on r'     foo bar \ baz quux\ .
I'd personally leave things with the last workaround (and not mention there are multiple), but if another workaround is desired, using two string literals with the terminal slash in a second one implicitly concatenated is the next-best-one to me:
fn = r'C:\this\will\work' '\\'

    
  
  



    

        
      
  
  
    
  
  
  
    
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            dancinglightning
  

      

      

      


        Aug 25, 2021



      
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      Yeah, I do agree it adds to the runtime but I am pretty sure that this piece of information can be invaluable and many times go unnoticed. I too faced difficulty in comprehending the issue when I got stuck with it. I was able to resolve it later by reading various discussions.
    
  
  



    

        
      
  
  
    
  
  
  
    
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+    Strings can be concatenated (glued together) with the ``+`` operator, and
+     repeated with ``*``::
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     String literals can span multiple lines.  One way is using triple-quotes:
     ``"""..."""`` or ``'''...'''``.  End of lines are automatically
     included in the string, but it's possible to prevent this by adding a ``\`` at
-          Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Added a discussion of trailing backslash in raw string to tutorial