I can reverse list order by using the reversed iterator or by using ::-1, as shown in this code: li=[1,2,3]  print(list(reversed(li))) print(li[::-1])  However, I have not understodde the meaning of the :: addressing, and I have not found any documentation on this feature (possible due to the fact that searching for :: creates problems). Can anyone help? Thank you.
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.
Creating fishnet grid with specified rotation angle in ArcGIS Desktop? I'm working on this project and I need a grid with a certain rotation, at about 60 degrees, for example.  Starting from that I need to make a block of 20mx50m, and the last thing is that inside each block there must be a small set of sub-blocks.   The result is this:    Of course it's been done manually, but I was thinking of a way of making it done automatically because I must do 30 blocks like this one, maybe more, and it is consuming a lot of my time. Voldemort ordered Nagini to kill Snape in hopes of claiming the Elder Wand's ownership.  Let's suppose that Snape was indeed the owner.  In this scenario, would the Elder Wand's ownership truly pass to Voldemort?  I ask this because, after all, the one who overpowered Snape was Nagini, not Voldemort.   Voldemort ordered Nagini to kill Snape. However, this would be equivalent to ordering a Death Eater to kill Snape, in which case the Death Eater would gain the ownership - in a similar manner, Nagini is the murderer. Nagini isn't a "spell": remember how Draco summoned a snake to attack Harry back at CoS? If that snake kills Harry, I'd imagine that Draco gains the ownership (if Harry had the Elder Wand) because that snake was a "spell" casted by Draco - but this time is different, because Nagini isn't a "spell" casted by Voldemort, but rather an actual third-party creature.   The curious thing is that Voldemort did cast some sort of spell (he flicked his wand), which I think caused Nagini's barrier to break so Nagini could kill Snape. In some way, Voldemort did provoke Snape's death - however, it was mostly indirectly.  So, would the ownership pass to Nagini or to Voldemort? If it passes to Nagini, would the Elder Wand's "ownership cycle" end, or would it continue if Voldemort decides to kill Nagini?    The simplified version of this question is: if an animal kills the owner of the Elder Wand, what happens to its ownership? What is the meaning of the term "linear" Sort Order on the User Filter is Surprising To Me When filling in the "Type to Find Users" , it seems to sort by exact match and then by reputation when I am on the reputation tab.   For example, please consider the following search results:    This threw me off since I thought that the sort order is reputation. I guess this often might give people what they want, but when picking a popular name is shows a lot of 0 rep users. Maybe adding a filter for low rep to the exact match might give more expected results, or just sorting on Rep? How do I check if a given string is a legal/valid file name under Windows? I want to include a batch file rename functionality in my application. A user can type a destination filename pattern and (after replacing some wildcards in the pattern) I need to check if it's going to be a legal filename under Windows. I've tried to use regular expression like [a-zA-Z0-9_]+ but it doesn't include many national-specific characters from various languages (e.g. umlauts and so on). What is the best way to do such a check? Pipe sound output to file? Can the editor for editing tag descriptions get updated to match the normal questions/answers editor? The text editor that is shown when editing tag descriptions still uses the previous behaviour for inserting links and images. Also, the placeholder text for links is still http:// instead of https:// compared to the new editor. Another &quot;nice to have&quot; feature that exists in the main editor is the ability to paste an image from clipboard directly to the text editor without having to press the &quot;insert image&quot; toolbar-icon first. Can it get updated to match the editor we use for questions and answers?  The following screenshot is an example of how it looks if I try to insert a link for a tag description:  In comparison, this is how it looks in the new editor: Do we ever get more information about the Entwives? During my recent re-reading of The Two Towers I was struck again by a question that has bothered me since I was a youngling: What on earth is up with the Entwives?  Treebeard says they went away in the distant past and just... got lost?  Did Tolkien ever make mention of them again, or is this one of those unsolved mysteries of Middle Earth? What is a good asymptotic for $f_n = f_{n-1}+\ln(f_{n-1})$? 2016: a year in closing How to prove that center of $GL_n(\mathbb R)$ is scalar matrices?  Again what can you say about the center of set of all upper triangular matrices and center of set of all diagonal matrices. Eeeeek - what happened to my @ salutation? The coefficient of $x^9$ in the expansion of $(1+x)(1+x^2)(1+x^3)...(1+x^{100})$.  I tried the following concept, how to sum 9 using 1-9 only without repetition.  1:9, 2:1+8,3:7+2, 4: 6+3, 5: 5+4,  6:1+2+6 ,7:1+3+5, 8:2+3+4  The answer is 8.  How will it be solved using Binomial theorem. Regular (non-moderator) users should be able to override deletions by Community user There is a question on  that got deleted by the Community user. This question isn't terrible (we have worse one's there), and I'm not complaining about this question in particular.  I wanted to vote to undelete it. However, it says "A moderator has deleted this post and it cannot be undeleted". This "moderator" is Community!  I understand if a "real" live human moderator (no offense to all non-humans out here) deleted this question that we can't override it. But this is a Robot! It sees that it got a downvote, no answer and little activity for a while and just deletes it.  Can we have "Community user" have rights to delete, but have those "deletions" subject to normal-person override? Passing Javascript variable to I have two submit buttons in a form. How do I determine which one was hit serverside? How can something happen when time does not exist? I saw  hosted by Stephen Hawkins.  And if I didn't get it wrong, it says that there was no time before the big bang, time was created there.  So how can anything happen when there is no time (eg: the creation of time and the universe)? Is this what he calls a 'singularity'? Which I could think like this: when there is no time nothing can happen, except during this singularity.  Of course I don't know of a law that says 'when there is no time nothing can happen..', I just came up with it, as something intuitive. What to do with an Ubuntu disk image that appears as a WinRAR file? Least upper bound not an element in the cut In his proof "Any bounded nonempty subset $\mathbb{R}$ has a least upper bound in $\mathbb{R}$", Enderton showed that the least upper bound is just $\bigcup A$. Since by definition $x\subseteq \bigcup A\quad \&amp; \quad x\in A$ . In the case $x=\bigcup A\quad \&amp; \quad x\in A$, $x$ becomes the largest element in $A$, but this cannot be true since the Dedekind Cut is a subset of $\mathbb{Q}$ that must have no largest element. How do you explain that? Do votes get canceled if voting privilege is lost? If I'm below 15 reputation, I can't alter the public score of an answer/question.  Suppose I gain the privilege by getting the required rep and vote some posts up. Then, for any reason, I fall below 15 and lose the ability to vote. What about the votes I already did cast?  Do post scores get altered by ignoring my vote, or will they stay the same? In other words, is losing a privilege retroactive?  If yes, what about when I gain my privilege back? Are my votes automatically restored, or do I have to cast them again from scratch?  I made the easiest example, but this applies to any higher privilege