Re: [portland] PEP 8 Line Length Compliance
Of course in the first syntax rule I mention I should have said:
Whenever you open a parenthesis, brace or bracket, every newline is
considered as plain space by the parser UNTIL YOU CLOSE THE
PARENTHESIS, BRACE OR BRACKET.
Which is rather obvious...
Best,
Luciano
On Thu, May 21, 2015 at 12:13 PM, Luciano Ramalho luci...@ramalho.org wrote:
You can escape the newline and the end of a line by typing \ as the
last character, but I think this is ugly and error prone and I avoid
it whenever I can -- which is almost always.
There are two syntax rules of Python that are not so well-known that
help avoiding the \:
- Whenever you open a parenthesis, brace or bracket, every newline is
considered as plain space by the parser. Very often, adding
parenthesis around an expression does not change it's meaning, so
that's one way to make one logical line span multiple physical lines
without resorting to \.
- Two or more string literals with no intervening tokens except
whitespace are parsed as a single string literal.
Putting those two rules together, the result is that this snippet:
text = ('a bb ccc e '
'ff ggg ')
Is exactly the same as this one, as far as the Python interpreter is
concerned:
text = 'a bb ccc e ff ggg hh'
But note that I appended a trailing space to the first string literal,
otherwise the parser would see this:
text = 'a bb ccc eff ggg hh'
HTH.
Best,
Luciano
On Thu, May 21, 2015 at 11:53 AM, Rich Shepard rshep...@appl-ecosys.com
wrote:
I use emacs for writing code (among other editing tasks) and have the line
length set to 78 characters. That's the recommended maximum line length in
PEP 8. However, when I have a lot of text for an import command, or within a
single-quoted string, python complains about unexpected endings if I break
the string with a newline prior to column 78.
Should I just ignore that PEP 8 suggestion or is there a line continuation
character (such as \) that can be applied?
Rich
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Luciano Ramalho
| Author of Fluent Python (O'Reilly, 2015)
| http://shop.oreilly.com/product/0636920032519.do
| Professor em: http://python.pro.br
| Twitter: @ramalhoorg
--
Luciano Ramalho
| Author of Fluent Python (O'Reilly, 2015)
| http://shop.oreilly.com/product/0636920032519.do
| Professor em: http://python.pro.br
| Twitter: @ramalhoorg
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Re: [portland] PEP 8 Line Length Compliance
You can escape the newline and the end of a line by typing \ as the
last character, but I think this is ugly and error prone and I avoid
it whenever I can -- which is almost always.
There are two syntax rules of Python that are not so well-known that
help avoiding the \:
- Whenever you open a parenthesis, brace or bracket, every newline is
considered as plain space by the parser. Very often, adding
parenthesis around an expression does not change it's meaning, so
that's one way to make one logical line span multiple physical lines
without resorting to \.
- Two or more string literals with no intervening tokens except
whitespace are parsed as a single string literal.
Putting those two rules together, the result is that this snippet:
text = ('a bb ccc e '
'ff ggg ')
Is exactly the same as this one, as far as the Python interpreter is concerned:
text = 'a bb ccc e ff ggg hh'
But note that I appended a trailing space to the first string literal,
otherwise the parser would see this:
text = 'a bb ccc eff ggg hh'
HTH.
Best,
Luciano
On Thu, May 21, 2015 at 11:53 AM, Rich Shepard rshep...@appl-ecosys.com wrote:
I use emacs for writing code (among other editing tasks) and have the line
length set to 78 characters. That's the recommended maximum line length in
PEP 8. However, when I have a lot of text for an import command, or within a
single-quoted string, python complains about unexpected endings if I break
the string with a newline prior to column 78.
Should I just ignore that PEP 8 suggestion or is there a line continuation
character (such as \) that can be applied?
Rich
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Luciano Ramalho
| Author of Fluent Python (O'Reilly, 2015)
| http://shop.oreilly.com/product/0636920032519.do
| Professor em: http://python.pro.br
| Twitter: @ramalhoorg
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Re: [portland] PEP 8 Line Length Compliance
On Thu, 21 May 2015, Luciano Ramalho wrote: You can escape the newline and the end of a line by typing \ as the last character, but I think this is ugly and error prone and I avoid it whenever I can -- which is almost always. Luciano, Thanks. That's what I commonly use, but haven't applied to python. - Whenever you open a parenthesis, brace or bracket, every newline is considered as plain space by the parser. Very often, adding parenthesis around an expression does not change it's meaning, so that's one way to make one logical line span multiple physical lines without resorting to \. This is how it works with long wxPython widget strings. I did not make the connection to enclosing characters. - Two or more string literals with no intervening tokens except whitespace are parsed as a single string literal. Unless the string is delineated with single quotes (as in a content list for a drop-down picklist control). :-) I'm used to seeing (and writing) newlines in bash scripts and other text so now I know python recognizes it I can use this solution. Much appreciated, Rich ___ Portland mailing list Portland@python.org https://mail.python.org/mailman/listinfo/portland
Re: [portland] PEP 8 Line Length Compliance
On Thu, May 21, 2015 at 12:24 PM, Rich Shepard rshep...@appl-ecosys.com wrote: On Thu, 21 May 2015, Luciano Ramalho wrote: - Two or more string literals with no intervening tokens except whitespace are parsed as a single string literal. Unless the string is delineated with single quotes (as in a content list for a drop-down picklist control). :-) The syntax I described works for any of the valid string delimiters in Python: single quotes, double quotes, triple single quotes and triple double quotes, and the adjacent string literals do not need to use the same delimiter, you can mix and match and they'll still be parsed as one big string literal. I'm used to seeing (and writing) newlines in bash scripts and other text so now I know python recognizes it I can use this solution. The problem with the trailing \ is if someone accidentally types a space after it, the newline is no longer escaped, and most editors don't highlight this error, so you get a confusing message from the interpreter. Best, Luciano Much appreciated, Rich ___ Portland mailing list Portland@python.org https://mail.python.org/mailman/listinfo/portland -- Luciano Ramalho | Author of Fluent Python (O'Reilly, 2015) | http://shop.oreilly.com/product/0636920032519.do | Professor em: http://python.pro.br | Twitter: @ramalhoorg ___ Portland mailing list Portland@python.org https://mail.python.org/mailman/listinfo/portland
Re: [portland] PEP 8 Line Length Compliance
I prefer Luciano's suggestions. That said, another way is to build up the
string from a list and then join the list elements. For your case this is
overkill:
l_res = list()
l_res.append('a bb ccc e ')
l_res.append('ff ggg ')
res = ''.join(l_res)
Robert
-Original Message-
From: Portland [mailto:portland-bounces+robert.lugg=synopsys@python.org] On
Behalf Of Luciano Ramalho
Sent: Thursday, May 21, 2015 8:42 AM
To: Python Users Group -- Portland, Oregon USA
Subject: Re: [portland] PEP 8 Line Length Compliance
On Thu, May 21, 2015 at 12:24 PM, Rich Shepard rshep...@appl-ecosys.com wrote:
On Thu, 21 May 2015, Luciano Ramalho wrote:
- Two or more string literals with no intervening tokens except
whitespace are parsed as a single string literal.
Unless the string is delineated with single quotes (as in a content
list for a drop-down picklist control). :-)
The syntax I described works for any of the valid string delimiters in
Python: single quotes, double quotes, triple single quotes and triple double
quotes, and the adjacent string literals do not need to use the same delimiter,
you can mix and match and they'll still be parsed as one big string literal.
I'm used to seeing (and writing) newlines in bash scripts and other
text so now I know python recognizes it I can use this solution.
The problem with the trailing \ is if someone accidentally types a space
after it, the newline is no longer escaped, and most editors don't highlight
this error, so you get a confusing message from the interpreter.
Best,
Luciano
Much appreciated,
Rich
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Luciano Ramalho
| Author of Fluent Python (O'Reilly, 2015)
| http://shop.oreilly.com/product/0636920032519.do
| Professor em: http://python.pro.br
| Twitter: @ramalhoorg
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