s = "alphabet" print(s[2:8:2])   this prints 'pae'  i understand that it starts counting from the left and starts from 0 so  0 = a 1 = l 2 = p 3 = h 4 = a 5 = b 6 = e 7 = t   so im not sure how the last :8 and :2] work
I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.
Analytic continuation of a power series 2 Another Qual question here,  For the function $$\sum_{n=0}^\infty z^{2^n}$$,  Prove the following:  i) $f$ converges to a function analytic in the open unit disk $D$,  ii) $f(z) =z+f(z^2)$ and  iii) $f(z)$ can not be analytically continued past any point on the unit circle.  I can even see (ii) very easily, but I can not see how can I prove rigorously (i) and  (iii). Help please. When you pass a collection like list, array to another function in python, does it make a copy of it, or is it just a pointer? I often get an error saying      unable to update ICE authority.    Is there a way out of this? Let's say I have a node type "Article" which has a field "File" which is set to handle public files. A lot of articles and files get added.  Now the specs suddenly change and the "Article" will move behind a login and therefore also the attached files must be changed to be not publicly accessible anymore.  I already found out  pretty easily by reimporting the manually updated field.storage.node.field_file.yml config. But: this only affects new files that will be added after the switch. It doesn't work for existing files. They still are accessible publicly. Many thousand existing files would need to be manually reuploaded to also make them private.  Does anybody of you have solved that in D8 before? If so, then how?  As all I can think of right now is to programmatically query all "Article" nodes, then foreach through all nodes, get the files, temporarily store them somewhere else, empty the field out, then try to reupload the files programmatically (probably my next question) and then resave each node.  Does that sound reasonable? Or can you think of any other approach that might work here (in D8)? What is the fastest algorithm for finding the natural logarithm of a big number? How to highlight (color/draw attention to) a particular snippet in Minted I'm currently doing some work on error messages in programming languages. As such, I'm showing faulty pieces of code, alongside the compiler-errors accompanying them.  I'm using minted for the code snippets, but ideally, in addition to normal syntax highlighting, I'd like to highlight the sections of the code at which the error is located, by underlining them, putting a red box around them, shading their background, etc.  Is this possible using Minted? How should strace be used? A colleague once told me that the last option when everything has failed to debug on Linux was to use .  I tried to learn the science behind this strange tool, but I am not a system admin guru and I didn’t really get results.  So,   What is it exactly and what does it do? How and in which cases should it be used? How should the output be understood and processed?   In brief, in simple words, how does this stuff work? How to display a video in a web page using html,php How to change desktop background from command line in Unity? I have a script that updates my desktop background every day with the NASA APOD. Since upgrading to 11.10, that script stopped working, presumably because I'm using gconftool-2 to actually update the desktop background. Is there a new way to do this under Unity? jQuery not working in Wordpress 3.5 How do I make a bootable USB OS X installer on a Mac? Does anyone have a Terminal command-line recipe for making a new bootable USB flash drive for one of the new MacBook Air's?  Is there a way to dd copy the USB boot device that comes in the box and make the new copy bootable?  I'd like to make a new backup copy of the USB rescue device for my MBA, preferably on a much larger flash drive with room for a backup of some of my working directories.  Added:  And is it possible to make, not just a rescue drive, but a bootable USB drive that will boot a fully updated version of the OS (say 10.6.8 or later)?  If so how on a MacBook Air 11, and how big a USB stick will this require? How can I get my usual interface when opening projects created by other people? I've bougth cup models from internet.   In the ZIP I get the blend file and pressing F12 I can render the project (Do you call it project?)  But I don't see anymore the "Layout" tab, that is what I use the most.   Why and how can I go back to my usual interface?    Like in the Opening Layout:    UPDATE 1  I could open the file with the default layout, however I'm not seeing the objects in there:    UPDATE 2  How to open Collection 1? It's grayed out. When punctuating the dimensions of something, if both dimensions share the same units, does the punctuation occur after each measurement or just after the last one. For example, if I'm looking at a sheet of paper, which is correct: {8 1/2 x 11"} or is {8 1/2" x 11"}? What's the nice 'trick' to showing that the following expression is irrational?  $2^{1/3} + 2^{2/3}$ Removing small spaces (slivers) between polygons? Prime ideal in a polynomial ring over an integrally closed domain a command to list all packagas installed on the system and their installed files, how? Riemann integrabilty of an indicator function Consider the following function on $[0,1]$:   $$f(x)=\begin{cases}1&amp;x\in\{a_1,a_2,\dots,a_n\}\\0 &amp;\text{otherwise}\end{cases}$$   The $a_i$ are fixed and all in $[0,1]$. Determine whether $f$ is Riemintegrable or not.   By the Riemann&ndash;Lebesgue criterion $f$ is Riemann integrable. How to prove directly? Direction of Friction on two stacked boxes Human vs. alien to avoid extinction by omnipotent being