So say I have a Class:   class Testclass:       def __init__(self, key)           self.key = key             def function(self, key):               do something ...     can I call specifically the function without calling the whole __init__ somewhere down the line inside a Testclass Method?  I need this because I have two functions within __init__ and I need them separately.   Or maybe I am doing this all wrong from the get go, so any other suggestions would be welcome.
What exactly are the Python scoping rules?  If I have some code:  code1 class Foo:    code2    def spam.....       code3       for code4..:        code5        x()   Where is x found?  Some possible choices include the list below:   In the enclosing source file In the class namespace In the function definition In the for loop index variable Inside the for loop   Also there is the context during execution, when the function spam is passed somewhere else. And maybe  pass a bit differently?  There must be a simple reference or algorithm somewhere.  It's a confusing world for intermediate Python programmers.
Why does python 2.5.2 have the following behavior  &gt;&gt;&gt;[2].extend([]) == [2] False  &gt;&gt;&gt; [2].extend([]) == None True  $ python --version Python 2.5.2   I assume I'm not understanding something here, but intuitively I'd think that [2].extend([]) should yield [2] Evaluate $$ 1 + \frac{1}{3}\frac{1}{4}+\frac{1}{5}\frac{1}{4^2}+\frac{1}{7}\frac{1}{4^3}+\dots$$  All i could do was to see that $$\frac{1}{3}=\frac{1}{2.1+1},\frac{1}{5}=\frac{1}{2.2+1},\frac{1}{7}=\frac{1}{2.3+1},\dots$$  SO, we should be able to write   $$ 1 + \frac{1}{3}\frac{1}{4}+\frac{1}{5}\frac{1}{4^2}+\frac{1}{7}\frac{1}{4^3}+\dots=1+\sum_{n=1}^{\infty}\frac{1}{2n+1}.\frac{1}{4^n}$$  This is what i could simplify the given question to...   But, this is doing me no good.. I could not go any further..  I would be thankful if some one can help me to clear this.  I would request users who are trying to help me to just give necessary hints but not post it as answer.  Thank You. VirtualBox: using physical partition as virtual drive Background: I am using VirtualBox installed on Windows 7. From within VirtualBox I am using Xubuntu as a virtual OS. The reason I chose this approach is so that I don't have to keep turning off Windows and rebooting from Xubuntu every time I needed to switch OSes. And VirtualBox's seamless mode is pretty amazing to allow me see Xubuntu and Windows 7 all in one screen.   Issue: Now I am thinking of a way to have Xubuntu more integrated into my system. By this I mean I want to have a physical partition for Xubuntu. But I want to still have the feeling of the seamless mode.  Question: So finally, my question is: is it possible to load a partition in VirtualBox as a virtual OS?   Case examples: Ideal scenario would be: I physically boot up and login to Windows 7. Now I want to access Xubuntu, so I load VirtualBox and access my Xubuntu partition without rebooting. And the other way around too, i.e. I boot up the system, login to Xubuntu, and can access the actual Windows 7 partition through VirtualBox.   Other info: Please note that I am not talking about getting access to files, as I have a completely separate partition for my files, and am very familiar with VirtualBox's Shared Folders option. Is it possible to mount on a PC an SD card that has been encrypted by an Android Marshmallow device? I have a Samsung Galaxy S5 duos with stock Android Marshmallow, and I'm considering encrypting my SD card to prevent access to its contents in case I lose my phone. The main reason of not doing this is that I'm not sure if there's a way to mount an encrypted SD card on Windows (or other desktop OS's)   When I encrypt the SD card on my Samsung Galaxy S5, is it using a known implementation of encryption, or is it something that only works on Android (or perhaps Samsung) phones?   I do not want to use USB connection to my phone to access my SD card, it's terrible. Mounting the SD card is much easier and faster and less annoying.   EDIT: just to clarify, I am NOT talking about adoptable storage. I want a portable encrypted SD card that can both be read on PCs and Android phones (i.e. I want to be able to remove the SD card from my phone, plug it into my PC, provide a password to decrypt and read/write it like any other SD card) Recently I came across a debate about whether it's fair to call RAW 'unprocessed' or 'unaltered' sensor data of a DSLR. As far as I know, the analog sensor data is processed into a digital RAW file using the ISO setting, a process during which the Bayer-sensor data is demosaiced as well. However, those are just the necessary steps for saving a digital file while maintaining maximum quality.  Are those assumptions correct? If so, are there any additional steps that need to be performed between the sensor receiving light and the saving of the RAW file? And can those be reasonably be described as an 'alteration' of the sensor data, or is it fair to say that a RAW file holds the unaltered sensor data? Transit Visa for Thailand Dealing with "java.lang.OutOfMemoryError: PermGen space" error How to compute $\lim_{n\rightarrow\infty}e^{-n}\left(1+n+\frac{n^2}{2!}\cdots+\frac{n^n}{n!}\right)$ There is a probabilistic method to solve it. But I am not familiar with probability. I am trying to compute it by analytic method, such as using L Hospital's rule or Stolz formula, but they are not working. Is it possible for a system to have negative potential energy? I've been writing in English for many years, but there are certain recurring issues that come up in my writing, which I can't seem to resolve permanently. Primarily I have a problem with punctuation. In my native language, commas are very commonly used. One would place a comma to separate any portion of the sentence that serves a specific grammatical role. At least, this is the case according to the rules I was taught in school. I can see when I write in English that there are extraneous commas, but I can't always figure out which ones, and why. When dependent clauses require commas, when do they allow them, and when are they definitely incorrect? How to "cat" or "less" a libreoffice writer .odt file? show that if $n\geq1$, $(1+{1\over n})^n<(1+{1\over n+1})^{n+1}$ In the digital age of photography, we can see a range of digital camera sensors sizes in use, from 1/3.2" in small phones, up to Medium format sensors that are 53.4 x 40.0mm in size or more!  Why has no company endevoured to produce a sensor that can be considered to be large format (50mm X 80mm or larger)? Do such camera sensors exist in non-consumer products? Should I use Yes/No or Ok/Cancel on my message box? Semantically, the Yes/No buttons are roughly equivalent to the Ok/Cancel buttons, but in general what would you recommend to use? Should I always use Yes/No or always use Ok/Cancel? Or does it depend on the case? Why are packages in the official Ubuntu repositories older than the latest (upstream) versions from Debian Sid, PPAs, the authors, etc.? How To Display Too Much Data We're building a web-based platform where the main dashboard shows a table of data for users to view and analyze. As we're growing this tool, we seem to be adding more and more columns and are running out of horizontal space on smaller screen resolutions (we're seeing some data wrap). It is important to the user to view all columns at once, so column hiding is somewhat out of the question, as is horizontal scrolling (per the boss's request and because horizontal scrolling sucks anyways). I was wondering if anyone knew of a clever UI for tables with many columns.  EDIT  Below is a screen capture of the layout of the table. Unfortunately for security purposes I had to blur out the column titles. This example has rows with practically no data in them, but in use they will have lots of data that will expand wider than their respective column titles. In response to some of the answers, it is imperative that the user see all the columns, as they are all necessary to analyze the data to make certain decisions. All the data is numeric aside from the first three columns. Thanks again for any feedback.    Ok so I see that uploading this image doesn't really do it justice... it takes up the full width of the screen at 1680x1050 resolution (22") and as data fills in the columns, the left column w/the text shrinks down a bit.  EDIT 2 I just wanted to say thank you to everyone's awesome ideas. I can only select one answer, but a lot of your ideas have proven very useful and may end up in the final product. Thanks again! Travelling on Business visa to UK for tourism purposes Using mask as a garbage matte to hide an object I'm trying to use a mask to hide a part of a render layer, so that when the render layer is shown over a movie, some parts in the movie will appear to be in front of the render layer.  For example, assume I want to add a box to this image, so that it would look like it's behind the person:    I created the following simple object:    If I render the object, it looks great - the object is solid, everything else is transparent (I didn't use any 'sky'):     Now I create a mask to describe the standing person (or at least the part that would otherwise be covered by the box):    What I want now is to create a "hole" in the rendered box, so that when I use Alpha-over, the box look as if it's behind the person, but I can't find an easy way to do that. My first guess was to use 'Set alpha' to apply the mask (inverted) as an alpha for the rendered layer, but this doesn't look good:    The mask did create a "hole" where it should, but now all the other pixels are not transparent. How can I "retain" the transparent pixels while setting more pixels to be transparent based on the mask (use it as a matte)?  Note: I can do this with (I'm ashamed to say) some math work on the alpha channel, but it just doesn't seem right:    Thanks, and sorry for the [oh so] long question. When trying to install CrossOver deb I get "Error: Dependency is not satisfiable libpng12-0" Does equality of characteristic polynomials guarantee equivalence of matrices? I have a qualifying exam coming up in a couple days and I am just trying to understand some pathological examples I have in my notes. I will list a similar problem which I know the solution to and then the question.  True or False:   let $A,B \in \mathbb{Q}^{n \times n }$  Suppose $xI-A$ and $xI-B$ are equivalent then $\det(xI-A) = \det(xI-B)$.     I wrote in my notes this is true because any two matrices are equivalent in $\mathbb{Q[x]}^{n \times n}$ if and only if they have the same invariant factors.  Since the characteristic polynomial is a product of the invariant factors it follows that $\det(xI-A) = \det(xI-B)$.        True or False:   let $A,B \in \mathbb{Q}^{n \times n }$. If $\det(xI-A) = \det(xI-B)$ (in $\mathbb{Q}[x]$) then $xI-A$ and $xI-B$ are equivalent  in $\mathbb{Q}[x]^{n \times n}$   I think this is false because of the fact that equality of determinants is not strong enough to guarantee all invariant factors are equal but I do not have an example.