I need to have this line in the beginning of a python file:
#script_exec_time: 500
There should not be any space between the # and script_exec_time. This is because the python file is parsed by another script and it will not consider the script_exec_time if there is a space.
I cannot modify the script that parses my python file because I do not have access to it.
Now when I lint using pylint, it automatically gives a space between the # and script_exec_time.
I tried using other linters like flake8, but even they do the same thing.
I still want to use the linter because it makes it much easier to code.
Is there any way to modify pylint settings so that it ignores comments from it's automatic formatting? Or is there any workaround I could use here?
Edit: I tried the same thing by disabling the linter. The problem persisted. It was not related to linter I think. Anyway I found a workaround and I am posting that as an answer.
As Vaibhav Vishal pointed out in his comment, linters like Pylint and flake8 do not reformat code, they just flag code that triggers a lint rule.
You most likely have a formatter installed and configured. See the formatting docs on how this is done and basically do the reverse. :)
All I did was to wrap the original comment in side a block comment, like so:
#script_exec_time:5000
'''
#scrript_exec_time:5000
'''
Vscode will not format anything that is there inside the block comments.
I am using PyDev with Eclipse and I have some attributes that are only set during runtime. Normally I can fix PyDev's errors like this:
obj.runtime_attr # #UndefinedVariable
However, since my statement is long and thus, with respect to PEP8, multiline, it looks like this:
some.long.statement.\
with.multiline(obj.runtime_attr).\
more()
Now I cannot add #UndefinedVariable because it breaks line continuation (PEP8 demands there are two spaces before a line-ending comment). However, I cannot put it in the end of the line (it just doesn't work):
some.long.statement.\
with.multiline(obj.runtime_attr).\
more() # #UndefinedVariable
Is there any way this could work that I am overlooking? Is this just a missing feature where you cannot get it right?
First, remember that the most important rule of PEP 8 is:
But most importantly: know when to be inconsistent -- sometimes the style guide just doesn't apply. When in doubt, use your best judgment. Look at other examples and decide what looks best.
And it specifically says to avoid a rule:
When applying the rule would make the code less readable, even for someone who is used to reading code that follows the rules.
That being said, you're already violating the letter and the spirit of PEP 8 just by having these lines of code, unless you can't avoid it without making things worse. As Maximum Line Length says, using backslash continuations is the least preferred way to deal with long lines. On top of that, it specifically says to "Make sure to indent the continued line appropriately", which you aren't doing.
The obvious way to break this up is to use some intermediates variables. This isn't C++; there's no "copy constructor" cost to worry about. In a real-life example (unlike this toy example), there are probably good names that you can come up with that will be much more meaningful than the long expression they replace.
intermediate = some.long.statement
multiline = intermediate.with.multiline(obj.runtime_attr)
more = multiline.more()
If that isn't appropriate, as PEP 8 explicitly says, it's better to rely on parenthetical continuations than backslash continuations. Is that doable here? Sure:
some.long.statement.with.multiline(
obj.runtime_attr).more()
Or, if worst comes to worst:
(some.long.statement.
with.multiline(obj.runtime_attr).more())
This sometimes makes things less readable rather than more, in which case you shouldn't do it. But it's always an option. And if you have to go to extraordinary lengths to make backslash continuation work for you, it's probably going to be worse than even the worst excesses of over-parenthetizing.
At any rate, doing things either of these ways means you can put a comment on the end of each line, so your problem never comes up in the first place.
I have tried a bunch of Python code folding plugins and I have seen this question asked once here, but they all don't seem to be too useful to achieve Python code folding in this manner:
class myClass(models.Model):
[folded code]
class Meta:
[folded code]
def __unicode__(self):
[folded code]
def save(self, *args, **kwargs):
[folded code]
So my question is, Is there any Python code folding plugin that can do this? I haven't been able to find any so far and I have tried out quite a number of such Vim plugins already.
description
Because of its reliance on significant whitespace rather than explicit block delimiters, properly folding Python code can be tricky. The Python syntax definition that comes bundled with Vim doesn't contain any fold directives at all, and the simplest workaround is to :set foldmethod=indent, which usually ends up folding a lot more than you really want it to.
There's no shortage of Vim plugins for improved Python folding, but most seem to suffer from cobbled-together algorithms with bizarre, intractable bugs in the corner cases. SimpylFold aims to be exactly what its name suggests: simple, correct folding for Python. It's nothing more than it needs to be: it properly folds class and function/method definitions, and leaves your loops and conditional blocks untouched. There's no BS involved: no screwing around with unrelated options (which several of the other plugins do), no choice of algorithms to scratch your head over (because there's only one that's correct); it just works, simply.
http://www.vim.org/scripts/script.php?script_id=3723
I almost always use set foldmethod=indent and it does almost what you want it to do (except for folding the class global variables).
see the help for how to tweak it.
I have been looking for the same thing, a folding method for python that leaves the entire method signature even when it spans multiple lines. This script worked for me. However, to get multiple line signatures to work, you'll want to add "let g:ifold_mode=2" to your .vimrc file.
I haven't used this script very long, so there may be other issues with it. Good luck!
I want to start using Python for small projects but the fact that a misplaced tab or indent can throw a compile error is really getting on my nerves. Is there some type of setting to turn this off?
I'm currently using NotePad++. Is there maybe an IDE that would take care of the tabs and indenting?
The answer is no.
At least, not until something like the following is implemented:
from __future__ import braces
No. Indentation-as-grammar is an integral part of the Python language, for better and worse.
Emacs! Seriously, its use of "tab is a command, not a character", is absolutely perfect for python development.
All of the whitespace issues I had when I was starting Python were the result mixing tabs and spaces. Once I configured everything to just use one or the other, I stopped having problems.
In my case I configured UltraEdit & vim to use spaces in place of tabs.
It's possible to write a pre-processor which takes randomly-indented code with pseudo-python keywords like "endif" and "endwhile" and properly indents things. I had to do this when using python as an "ASP-like" language, because the whole notion of "indentation" gets a bit fuzzy in such an environment.
Of course, even with such a thing you really ought to indent sanely, at which point the conveter becomes superfluous.
I find it hard to understand when people flag this as a problem with Python. I took to it immediately and actually find it's one of my favourite 'features' of the language :)
In other languages I have two jobs:
1. Fix the braces so the computer can parse my code
2. Fix the indentation so I can parse my code.
So in Python I have half as much to worry about ;-)
(nb the only time I ever have problem with indendation is when Python code is in a blog and a forum that messes with the white-space but this is happening less and less as the apps get smarter)
I'm currently using NotePad++. Is
there maybe an IDE that would take
care of the tabs and indenting?
I liked pydev extensions of eclipse for that.
I do not believe so, as Python is a whitespace-delimited language. Perhaps a text editor or IDE with auto-indentation would be of help. What are you currently using?
No, there isn't. Indentation is syntax for Python. You can:
Use tabnanny.py to check your code
Use a syntax-aware editor that highlights such mistakes (vi does that, emacs I bet it does, and then, most IDEs do too)
(far-fetched) write a preprocessor of your own to convert braces (or whatever block delimiters you love) into indentation
You should disable tab characters in your editor when you're working with Python (always, actually, IMHO, but especially when you're working with Python). Look for an option like "Use spaces for tabs": any decent editor should have one.
I agree with justin and others -- pick a good editor and use spaces rather than tabs for indentation and the whitespace thing becomes a non-issue. I only recently started using Python, and while I thought the whitespace issue would be a real annoyance it turns out to not be the case. For the record I'm using emacs though I'm sure there are other editors out there that do an equally fine job.
If you're really dead-set against it, you can always pass your scripts through a pre-processor but that's a bad idea on many levels. If you're going to learn a language, embrace the features of that language rather than try to work around them. Otherwise, what's the point of learning a new language?
Not really. There are a few ways to modify whitespace rules for a given line of code, but you will still need indent levels to determine scope.
You can terminate statements with ; and then begin a new statement on the same line. (Which people often do when golfing.)
If you want to break up a single line into multiple lines you can finish a line with the \ character which means the current line effectively continues from the first non-whitespace character of the next line. This visually appears violate the usual whitespace rules but is legal.
My advice: don't use tabs if you are having tab/space confusion. Use spaces, and choose either 2 or 3 spaces as your indent level.
A good editor will make it so you don't have to worry about this. (python-mode for emacs, for example, you can just use the tab key and it will keep you honest).
Tabs and spaces confusion can be fixed by setting your editor to use spaces instead of tabs.
To make whitespace completely intuitive, you can use a stronger code editor or an IDE (though you don't need a full-blown IDE if all you need is proper automatic code indenting).
A list of editors can be found in the Python wiki, though that one is a bit too exhausting:
- http://wiki.python.org/moin/PythonEditors
There's already a question in here which tries to slim that down a bit:
https://stackoverflow.com/questions/60784/poll-which-python-ideeditor-is-the-best
Maybe you should add a more specific question on that: "Which Python editor or IDE do you prefer on Windows - and why?"
Getting your indentation to work correctly is going to be important in any language you use.
Even though it won't affect the execution of the program in most other languages, incorrect indentation can be very confusing for anyone trying to read your program, so you need to invest the time in figuring out how to configure your editor to align things correctly.
Python is pretty liberal in how it lets you indent. You can pick between tabs and spaces (but you really should use spaces) and can pick how many spaces. The only thing it requires is that you are consistent which ultimately is important no matter what language you use.
I was a bit reluctant to learn Python because of tabbing. However, I almost didn't notice it when I used Vim.
If you don't want to use an IDE/text editor with automatic indenting, you can use the pindent.py script that comes in the Tools\Scripts directory. It's a preprocessor that can convert code like:
def foobar(a, b):
if a == b:
a = a+1
elif a < b:
b = b-1
if b > a: a = a-1
end if
else:
print 'oops!'
end if
end def foobar
into:
def foobar(a, b):
if a == b:
a = a+1
elif a < b:
b = b-1
if b > a: a = a-1
# end if
else:
print 'oops!'
# end if
# end def foobar
Which is valid python.
Nope, there's no way around it, and it's by design:
>>> from __future__ import braces
File "<stdin>", line 1
SyntaxError: not a chance
Most Python programmers simply don't use tabs, but use spaces to indent instead, that way there's no editor-to-editor inconsistency.
I'm surprised no one has mentioned IDLE as a good default python editor. Nice syntax colors, handles indents, has intellisense, easy to adjust fonts, and it comes with the default download of python. Heck, I write mostly IronPython, but it's so nice & easy to edit in IDLE and run ipy from a command prompt.
Oh, and what is the big deal about whitespace? Most easy to read C or C# is well indented, too, python just enforces a really simple formatting rule.
Many Python IDEs and generally-capable text/source editors can handle the whitespace for you.
However, it is best to just "let go" and enjoy the whitespace rules of Python. With some practice, they won't get into your way at all, and you will find they have many merits, the most important of which are:
Because of the forced whitespace, Python code is simpler to understand. You will find that as you read code written by others, it is easier to grok than code in, say, Perl or PHP.
Whitespace saves you quite a few keystrokes of control characters like { and }, which litter code written in C-like languages. Less {s and }s means, among other things, less RSI and wrist pain. This is not a matter to take lightly.
In Python, indentation is a semantic element as well as providing visual grouping for readability.
Both space and tab can indicate indentation. This is unfortunate, because:
The interpretation(s) of a tab varies
among editors and IDEs and is often
configurable (and often configured).
OTOH, some editors are not
configurable but apply their own
rules for indentation.
Different sequences of
spaces and tabs may be visually
indistinguishable.
Cut and pastes can alter whitespace.
So, unless you know that a given piece of code will only be modified by yourself with a single tool and an unvarying config, you must avoid tabs for indentation (configure your IDE) and make sure that you are warned if they are introduced (search for tabs in leading whitespace).
And you can still expect to be bitten now and then, as long as arbitrary semantics are applied to control characters.
Check the options of your editor or find an editor/IDE that allows you to convert TABs to spaces. I usually set the options of my editor to substitute the TAB character with 4 spaces, and I never run into any problems.
Yes, there is a way. I hate these "no way" answers, there is no way until you discover one.
And in that case, whatever it is worth, there is one.
I read once about a guy who designed a way to code so that a simple script could re-indent the code properly. I didn't managed to find any links today, though, but I swear I read it.
The main tricks are to always use return at the end of a function, always use pass at the end of an if or at the end of a class definition, and always use continue at the end of a while. Of course, any other no-effect instruction would fit the purpose.
Then, a simple awk script can take your code and detect the end of block by reading pass/continue/return instructions, and the start of code with if/def/while/... instructions.
Of course, because you'll develop your indenting script, you'll see that you don't have to use continue after a return inside the if, because the return will trigger the indent-back mechanism. The same applies for other situations. Just get use to it.
If you are diligent, you'll be able to cut/paste and add/remove if and correct the indentations automagically. And incidentally, pasting code from the web will require you to understand a bit of it so that you can adapt it to that "non-classical" setting.