Moving it to a function is common, if it doesn&#39;t touch the class at all.

If it manipulates class attributes, use the `classmethod` decorator:

    @classmethod
    def spam(cls, ...):
       # cls is the class, you can use it to get class attributes

`classmethod` and `staticmethod` (which is the same as the former, except that the method doesn&#39;t get a reference to the class from its first parameter) have been introduced quite recently.
It means that some Python programmers are used to avoid static and class methods.

Some hardcore Python programmers will tell you that these decorators just complicate things; some other people (usually former C# or Java programmers) will tell you that using a function isn&#39;t object-oriented enough.
I think it&#39;s just a matter of preference.

I&#39;m currently using regular expressions to search through RSS feeds to find if certain words and phrases are mentioned, and would then like to extract the text on either side of the match as well. For example:

    String = &quot;This is an example sentence, it is for demonstration only&quot;
    re.search(&quot;is&quot;, String)
I&#39;d like to know the position(s) of where the &#39;is&#39; matches are found so that I can extract and output something like this:  

    1 match found: &quot;This is an example sentence&quot;

I know that it would be easy to do with splits, but I&#39;d need to know what the index of first character of the match was in the string, which I don&#39;t know how to find

Python - Locating the position of a regex match in a string?

I feel this should be very simple but my brain is short-circuiting on it. If I have an object representing the current user, and want to query for all users except the current user, how can I do this, taking into account that the current user can sometimes be `nil`?

This is what I am doing right now:

    def index
      @users = User.all
      @users.delete current_user
    end

What I don&#39;t like is that I am doing post-processing on the query result. Besides feeling a little wrong, I don&#39;t think this will work nicely if I convert the query over to be run with `will_paginate`. Any suggestions for how to do this with a query? Thanks.

Rails ActiveRecord: Find All Users Except Current User

I have a python class and ran pylint against it. One message it gave was:

    Warning: Method could be a function

Is this telling me that it would be better to move this method out of the class because it doesn&#39;t use any instance variables? 

In C# I would make this a static method. What&#39;s the most pythonic thing to do here? 

How to handle the pylint message: Warning: Method could be a function

I have a python class and ran pylint against it. One message it gave was:
<pre><code class="hljs language-sql">Warning: Method could be a function
</code></pre>
Is this telling me that it would be better to move this method out of the class because it doesn't use any instance variables?
In C# I would make this a static method. What's the most pythonic thing to do here?

Is there a way to grab a list of attributes that exist on instances of a class?

    class new_class():
        def __init__(self, number):
            self.multi = int(number) * 2
            self.str = str(number)
    
    a = new_class(2)
    print(&#39;, &#39;.join(a.SOMETHING))

The desired result is that &quot;multi, str&quot; will be output.  I want this to see the current attributes from various parts of a script.

List attributes of an object

I&#39;m reading about sqlalchemy and I saw following code:

    employees_table = Table(&#39;employees&#39;, metadata,
        Column(&#39;employee_id&#39;, Integer, primary_key=True),
        Column(&#39;name&#39;, String(50)),
        Column(&#39;manager_data&#39;, String(50)),
        Column(&#39;engineer_info&#39;, String(50)),
        Column(&#39;type&#39;, String(20), nullable=False)
    )

    employee_mapper = mapper(Employee, employees_table, \
        polymorphic_on=employees_table.c.type, polymorphic_identity=&#39;employee&#39;)
    manager_mapper = mapper(Manager, inherits=employee_mapper, polymorphic_identity=&#39;manager&#39;)
    engineer_mapper = mapper(Engineer, inherits=employee_mapper, polymorphic_identity=&#39;engineer&#39;)


Should I make &#39;type&#39; an int, with constants in a library?  Or should I make just make type an enum?

Best way to do enum in Sqlalchemy?

I am trying to find out the version of Visual Studio that is used to compile the Python on my computer

It says 

&lt;!-- language: lang-none --&gt;

    Python 2.6.2 (r262:71605, Apr 14 2009, 22:40:02) [MSC v.1500 32 bit (Intel)] on win32

What I do not understand is this `MSC V.1500` designation. Does it mean it is compiled with Visual Studio 2005? I cannot find this information on http://python.org.

What version of Visual Studio is Python on my computer compiled with?

Given a function object, how can I get its signature? For example, for:

    def my_method(first, second, third=&#39;something&#39;):
        pass

I would like to get `&quot;my_method(first, second, third=&#39;something&#39;)&quot;`.

How can I read a function&#39;s signature including default argument values?

There are lots of times where I&#39;m not sure whether a particular method should be made private or not. For example, I&#39;m building a class right now, which, is responsible for generating a report. This class has a buildReport method and several methods which collect the necessary data for buildReport. 

    // single public method
    // uses a set of helper methods
    public buildReport()
    
    // helper methods
    private avgSurveyTime()
    private fetchVendors()
    private fetchSendCounts()
    private ...

I&#39;m debating whether I should make these helper methods public. The only method I really plan on calling outside at the moment is `buildReport()`. However, it might be useful to get just a list of the vendors with `fetchVendors()` etc. 

I see two schools of thought on this: You can always expose as little as possible. (In which case, many of my classes would only have one public method) OR you can expose all you can that might be useful to the user of the class.

Is there a good rule of thumb to use for deciding when methods should be made public/private?

When should methods be made private?

Should I give my class members default values like this:

    class Foo:
        num = 1

or like this?

    class Foo:
        def __init__(self):
            self.num = 1

In [this question][1] I discovered that in both cases,

    bar = Foo()
    bar.num += 1

is a well-defined operation.

I understand that the first method will give me a class variable while the second one will not. However, if I do not require a class variable, but only need to set a default value for my instance variables, are both methods equally good? Or one of them more &#39;pythonic&#39; than the other?

One thing I&#39;ve noticed is that in the Django tutorial, [they use the second method to declare Models.][2] Personally I think the second method is more elegant, but I&#39;d like to know what the &#39;standard&#39; way is.

[2]: http://docs.djangoproject.com/en/dev/intro/tutorial01/#id3

[1]: https://stackoverflow.com/questions/2424451/about-python-class-and-instance-variables

How should I declare default values for instance variables in Python?

One stumbles upon this phrase when reading about design patterns.

But I don&#39;t understand it, could someone explain this for me?

What does &quot;program to interfaces, not implementations&quot; mean?

**In terms that an OOP programmer would understand (without any functional programming background), what is a monad?**

What problem does it solve and what are the most common places it&#39;s used?

### Update

To clarify the kind of understanding I was looking for, let’s say you were converting an FP application that had monads into an OOP application. What would you do to port the responsibilities of the monads to the OOP app?


Monad in plain English? (For the OOP programmer with no FP background)

What is the purpose of the `self` word in Python? I understand it refers to the specific object instance created from that class. But why does it explicitly need to be added to every function as a parameter? To illustrate, in Ruby I can do this:

```ruby
class MyClass
    def func(name)
        @name = name
    end
end
```

However, in Python I need to include `self`:

```python
class MyClass:
    def func(self, name):
        self.name = name
```

What is the purpose of the word &#39;self&#39;?

I have a line like this:

    filter(lambda x: x == 1, [1, 1, 2])

Pylint is showing a warning:

    W:  3: Used builtin function &#39;filter&#39;

Why is that? is a list comprehension the recommended method?

Of course I can rewrite this like this:

    [x for x in [1, 1, 2] if x == 1]

And I get no warnings, but I was wondering if there&#39;s a PEP for this?

Why doesn&#39;t Pylint like built-in functions?

I&#39;m using PyQt and am running into this issue.  If my import statements are:

    from PyQt4.QtCore import *
    from PyQt4.QtGui import *

then pylint gives hundreds of &quot;Unused import&quot; warnings.  I&#39;m hesitant to just turn them off, because there might be other unused imports that are actually useful to see.  Another option would be to do this:

    from PyQt4.QtCore import Qt, QPointF, QRectF
    from PyQt4.QtGui import QGraphicsItem, QGraphicsScene, ...

and I end up having 9 classes on the QtGui line.  There&#39;s a third option, which is:

    from PyQt4 import QtCore, QtGui

and then prefix all the classes with QtCore or QtGui whenever I use them.

At this point I&#39;m agnostic as to which one I end up doing in my project, although the last one seems the most painful from my perspective.  What are the common practices here?  Are there technical reason to use one style over the other?

Should wildcard import be avoided?

I&#39;m trying to disable warning C0321 (&quot;more than one statement on a single line&quot; -- I often put `if` statements with short single-line results on the same line), in Pylint 0.21.1 (if it matters: astng 0.20.1, common 0.50.3, and Python 2.6.6 (r266:84292, Sep 15 2010, 16:22:56)).

I&#39;ve tried adding `disable=C0321` in the Pylint configuration file, but Pylint insists on reporting it anyway. Variations on that line (like `disable=0321` or `disable=C321`) are flagged as errors, so Pylint *does* recognize the option properly. It&#39;s just ignoring it.

Is this a Pylint bug, or am I doing something wrong? Is there a way around this?

I&#39;d really like to get rid of some of this noise.




How do I disable a Pylint warning?

In Python, if some methods of a class need a helper function, but the helper function itself doesn&#39;t use anything in the class, should I put the helper function inside or outside the class?

I tried putting it inside but PyLint was complaining that this function could have been put outside.

@Karl:

The class is a software upgrader and the helper function creates a new folder if the folder doesn&#39;t exist yet. The class is in a module having pretty much only the code for the class as of now. Other classes may be added later on.

Python - Should I put my helper functions inside or outside the class?

Pylint throws errors that some of the files are missing docstrings. I try and add docstrings to each class, method and function, but it seems that Pylint also checks that files should have a docstring at the beginning of them. Can I disable this somehow?

I would like to be notified of a docstring is missing inside a class, function or method, but it shouldn&#39;t be mandatory for a file to have a docstring.

(Is there a term for the legal jargon often found at the beginning of a proprietary source file? Any examples? I don&#39;t know whether it is a okay to post such a trivial question separately.)


Content Type	Original Author	Original Content on Stackoverflow
Question	bignum	View Question on Stackoverflow
Solution 1 - Python	Bastien Léonard	View Answer on Stackoverflow

How to handle the pylint message: Warning: Method could be a function

Python Problem Overview

Python Solutions

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Rails ActiveRecord: Find All Users Except Current User

Python - Locating the position of a regex match in a string?

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