how to perform operations with operator symbol saved in a variable
How to mathematically evaluate a string like "2-1" to produce "1"?
Inline image alignment issue for app and mobile web Opportunity attack when moving in and out of range of a creature in the same move? Let's say I'm 10ft away from an enemy. In my turn, I choose to move 5ft to get close enough to attack, I do attack, then I use my remaining movement to move out of range of the enemy. Does this still allow them an opportunity attack? How do you choose Spells Known when creating a new character above 1st level? It's not clear to me how to choose Spells Known when creating a new character at a higher level.  Let's take the Bard as a working example first:  Bard level 2:   Spells Known: 5 Slots per Spell level: 1st &times; 3   Bard level 3:   Spells Known: 6 Slots per Spell level: 1st &times; 4, 2nd &times; 2   I'm interpreting this to mean that, if an existing 2nd-level Bard gains a new level (level 3), he's gaining 1 (one) new spell known. He can then choose the new spell known to be either 1st or 2nd, correct?  What I don't understand then, is the case of creating a new character starting at a higher level; say, creating a new Bard at level 3.  In that case you're forced to choose 6 spells, which must be from the list of 1st- and 2nd-level spells, correct?  When making this 3rd-level Bard from scratch, though, can I select 2nd level spells for all 6 spells known?  As another example, say you're creating a very high level Bard from scratch, starting at level 15. The book says your Spells Known is 19, and your spell slots are 1st × 4, 2nd × 3, 3rd × 3, 4th × 3, 5th × 2, 6th × 1, 7th × 1, and 8th × 1.  So, for those 19 Spells Known, you can choose any spells from 1st through 8th spell level. Am I free then to select as many spells as I can at 8th spell level (5 in number), working backwards, and in the end ignoring the 1st, 2nd, 3rd level spells entirely?  As another example, the Ranger doesn't know any spells at 1st level, nor have any spell slots, but the book says “You know two 1st-level spells of your choice from the ranger spell list.” Does it mean at 2nd level and above?  Long story short: When choosing Spells Known for a spellcasting character created above 1st level, am I allowed to choose my Spells Known at whatever spell level I like, just so long as I have at least one spell slot of that level?  I'm working on a D&amp;D 5e character generator and need to clarify this. Prove that $Y=-2\sum_{i=1}^n \ln F_{X_i}(X_i)$ have distribution $\chi^2(2n)$ Finding distance between consecutive points using ArcGIS Desktop? How many RSA keys before a collision? I was wondering how many possible private/public keys exist? If a million people – for whatever reason – would try to generate 5 keys each in the same minute (on the same date and time) is there a high chance of collision? I believe GUID would suffer from that problem as many bits are reversed for date/time (and GUID version) and isn't meant to be used in that way.  Would RSA suffer from collisions if many keys were to be generated in the same moment? Is the amount of possible keys known? I know RSA is based on prime numbers and small numbers are to be rejected. I’m sure values above a certain amount of digits/bits are rejected because software may not be able to support those large values?  So: How many RSA keys before a collision? And if you would try to make many at the same time, would that give you a high chance of collision? Conditional Rendering inside Visualforce pages Access parent's parent from javascript object How check with SOQL if a picklist value is available or not for a specified record type How check if a picklist value is available or not for a specified record type ( through SOQL)? Thanks in advance How do I do a case-insensitive string comparison? How can I do case insensitive string comparison in Python?  I would like to encapsulate comparison of a regular strings to a repository string using in a very simple and Pythonic way. I also would like to have ability to look up values in a dict hashed by strings using regular python strings. I accidentally moved all folders from root to a subfolder. (/bin, /etc, /home, /lib, /usr... all moved) The only ones that were not moved, since they were in use, are  /bak, /boot, /dev, /proc, /sys.  Now, any command that I try to execute will simply not happen. I constantly get "No such file or directory".  I am connected through ssh and through ftp, but I cannot move files through ftp, as direct SU login is disabled. I also have access to the actual server if I need to do something directly from there.  I'm assuming I would need to edit a configuration file in order to tell it where to find the /bin folder and that would help me get access again, but I don't know which file that would be or how to do it (since I can't even run chmod to change permissions).  Is there any way out of this other than re-installing?  I am working on an old version of CentOS.  I'm extremely new to the world of Linux, hence this action and the question... It is will known that increasing cooling of a metal casting will lead to finer micro-structure which mean higher mechanical properties. If I have 2 molds one is thick copper die ,&amp; second is just thin-walled copper cup or mold cooled by water. which one of them excepted to cool the molten metal i.e. aluminium faster ?   by calculation it seems that copper die have higher cooling power as it has higher thermal diffusivity , but in real life it seems water have more cooling power. I am so confused. How to prepare files for rsync on a case insensitive filesystem? I am transferring a large number of files on a HFS+ filesystem.  The files are currently on ext2 partitions.  I have conflicts due to case insensitivity of the target partition (HFS+).  I want to identify the files that have duplicates filenames once they are in lower case, and delete them if they are actually duplicates.  I also found that I will have duplicate folder names if I convert everyhing to lower case. Basically these hard drives contain years of unsorted data, and I happen to have this problem with folder names too.   Does this seem reasonable:  find . -type f | while read f; do echo $f:l; done | sort | uniq -d    $f:l is ZSH for convert to lower case.  Now I want to keep only one instance of each file that have duplicates. How to do this efficiently ?  I do not want to find files with duplicate content, unless they have the same lower case filename. I will deal with duplicates later. Sorry for the title, it is not very evident and intuitive but I really do not how to tell it better...  Well, you know, several times, or better, many times, we use this form:  If I want to say:      "development of special weapons was   the first point in Hitler's   program..."   I will say this (a better form):      "special weapon development was..."   OK...  is it      "special weapon development"   or      "special weapons development" (note   the plural...)   what's the grammar rule in order to understand how to use this very used form? The error I am having when trying to update my package list.  W: GPG error: http://download.opensuse.org ./ Release: The following signatures were invalid: KEYEXPIRED 1436387333  W: Failed to fetch http://ppa.launchpad.net/samrog131/ppa/ubuntu/dists/trusty/main/binary-amd64/Packages  404  Not Found  E: Some index files failed to download. They have been ignored, or old ones used instead. How can we differentiate between change and progress in the area of history and natural sciences? In what kind of rings a divisor of a product is a product of divisors? In a , if $a|bc$, then $a$ can be written as $a = a_1a_2$ so that $a_1|b$ and $a_2|c$.  Is this property of a commutative ring strictly weaker than the property of being a UFD?  If so, does it have a name, or is it equivalent to some other well-known property? Is there a way to show the console in a Windows application?  I want to do something like this:  static class Program {     [STAThread]     static void Main(string[] args) {         bool consoleMode = Boolean.Parse(args[0]);          if (consoleMode) {             Console.WriteLine("consolemode started");             // ...         } else {             Application.EnableVisualStyles();             Application.SetCompatibleTextRenderingDefault(false);             Application.Run(new Form1());         }     } } Defend against flag spam in chat We have incidents where we get 10+ flags from the same room in rapid succession. This happens on multiple occasions and we have reason to believe it's a single user doing this.  I don't think it's of value to allow a single user to flag more then n messages in a small time period.  If we could have some anti-flag spam measures put in place, then that would be great. How to use variables inside single quotes