Two Apple Developer Accounts
Multiple Apple Developer Accounts
Iterating through a Collection, avoiding ConcurrentModificationException when removing objects in a loop We all know you can't do the following because of ConcurrentModificationException:  for (Object i : l) {     if (condition(i)) {         l.remove(i);     } }   But this apparently works sometimes, but not always. Here's some specific code:  public static void main(String[] args) {     Collection&lt;Integer&gt; l = new ArrayList&lt;&gt;();      for (int i = 0; i &lt; 10; ++i) {         l.add(4);         l.add(5);         l.add(6);     }      for (int i : l) {         if (i == 5) {             l.remove(i);         }     }      System.out.println(l); }   This, of course, results in:  Exception in thread "main" java.util.ConcurrentModificationException   Even though multiple threads aren't doing it. Anyway.  What's the best solution to this problem? How can I remove an item from the collection in a loop without throwing this exception?  I'm also using an arbitrary Collection here, not necessarily an ArrayList, so you can't rely on get. Academic rank equivalence between the UK and the US systems What are good advanced LaTeX books? I've been using LaTeX for about 3 months, and I'm hooked. My background is programming, so for the basic, google is sufficient. I did some research on amazon.com and found these two books with many positive feedback:    However, most of people said they are more like references than a real book. And if they really are, then I think I'd rather look up at CTAN. What I'm looking for is a book that can teach me how to program in LaTeX, for example:   Write my own package   Create animation  Create and using macro in LaTeX ....   I know there are many options around, however to pick the right one is not an easy task. Any advice or suggestion would be greatly appreciated. Thank you. What happens when a caster targets an object that looks like a creature with a spell that targets only creatures? There are many spells which explicitly target creatures:     Choose one creature within range   The target creature is normally supposed to make a saving throw in this case.  What happens when the caster chooses a creature, that is actually an object? For instance, a scarecrow, a mannequin, an illusion, or a corpse.  Examples:   An evil mage is hiding in the bushes. He casts an illusion of himself on the road, using the Silent Image spell. A PC sorcerer walks down the road, sees the illusion and casts Magic Missile on it. A cleric is standing near a pile of dead bodies. He has suspicions that a few corpses are actually undead creatures. He casts Sacred Flame on every corpse, see which if them succeed, hence, reveals the undead. A wizard casts Acid Splash on a mannequin, trying to damage it with acid.   Possible outcomes I can think of are:   The caster cannot even try to cast the spell, regardless of their information about what the target actually is. The caster tries to cast the spell, the casting fails, not expending the spell slot. The caster casts the spell, it expends the spell slot, then fails. The caster casts the spell, but it hits the original and not the illusion. The caster casts the spell, it flies to the target illusion but deals no damage to it (passes through it).   References in the rules and Sage advice  I was trying to investigate, but it didn't make things clearer:    has an answer, that Magic Missile won't hit. It says nothing about if it can be targeted at all, it leaves it up to the DM. Magic Missile automatically finds the original, even when the caster targets an illusion. At least . Now . This supports the counter-intuitive option 4.   on the other hand   , if there were no perceivable effects (let's say you can try to cast the Command spell on an illusion). That assumes that casters can waste their spells on illusion, which means they at least can target it. This supports options 3 and 5. Finding the derivative of $x\uparrow\uparrow n$ I am trying to find a general derivative for the function: $f(x)=x^{x^{x^{...^{x}}}}$however to do that I must find $f^{\prime }$ and $f^{\prime \prime}$...etc. I am now trying to write down a general expression for $f^{\prime \prime}$ and I have stumble opon the series in the picture below, I wonder, do anyone have an idea of what sort of expantion it migth be ? I have tried breaking it down into three different sums, but I wasn't very successful!  EDIT  So since this post has gotten some attention and the title has been change I will tell you what I am on about, although I already have a post just for the question in the title from before. I am as I said earlier trying to find a general derivative for the function $f(x)=x^{x^{x^{...^{x}}}}$ where $n$ is an arbitrary number, natural number and greater or equal to 2. I have already made success when I tried to find the first derivative, and I have also found some interesting pattern emerge when the derivatives as well as n incresses. But my question here was if anyone knew what this expation might be or look similar to be, since I have yet to be lernt series etc. I did not know that the question needed such background since it's straight a forward question. Format not available in tag wiki excerpt For example, :   Format like bold or italic are not available , so it leaves ugly text there:  **This tag is *extremely* ambiguous. Consider using other tags instead.**    Does this need to get fixed, or it's not supported and the tag-wiki needs to be format-free? Expandably change letter case and use inside \csname, without a package I want to change the letter-case of a single character argument, and use that changed letter inside a \csname.  And I want to do it without an additional package.  For example, I want to pass a macro the letter {S}, and have it execute the macro \csname macros\endcsname, or pass it the letter {T}, and have it execute the macro \csname macrot\endcsname.    In my MWE, I show three approaches:   I didn't expect \lowercase to work, since I recall reading that it is not truly expanded until the last possible moment.  Surprisingly, it goes into an \edef okay, but it must not be truly expanded, because it breaks the \csname. I also formulated an approach where I used \numexpr to add 32 to the ASCII code of the argument and perform a \char upon that result.  Like \lowercase, it gives the appearance of being expandable, but it also fails inside the \csname. I finally achieve success with the stringstrings package.  Having written the package, I know the conversion was not pretty... essentially, it is an exhaustive 26-fold check of the form \if #1Aa\else\if #1Bb\else\if #1Cc\else...\fi\fi\fi, which has the virtue that it can be expandably placed into an \edef, and so it works.   There has to be a better way.  The MWE works only because I use the inefficiently calculated \tmp from METHOD 3 inside the \csname.  If I use \tmp from either of the two earlier methods, it breaks.  \documentclass{article} \usepackage{stringstrings} \def\macros{Expandably converted an S to a s} \def\macrot{Expandably converted a T to a t} \newcommand\convert[1]{%   %MAKE THE ARGUMENT LOWER CASE   1) LOWERCASE\\   \edef\tmp{\lowercase{#1}}% PRETENDS TO EXPAND, BUT FAILS IN \csname   Here is the ``expanded'' conversion: \tmp\\   % OR   2) ASCII CONVERSION\\   \edef\tmp{\expandafter\char\numexpr`#1+32\relax}% PRETENDS TO EXPAND, BUT FAILS IN \csname   Here is the ``expanded'' conversion: \tmp\\   % OR   3) STRINGSTRINGS PACKAGE\\   \caselower[q]{#1}\def\tmp{\thestring}% WORKS BUT USES A PACKAGE   Here is the ``expanded'' conversion: \tmp\\   %   Now use it in a csname: \csname macro\tmp\endcsname% } \begin{document} \convert{S}\par \convert{T} \end{document}       SUMMARY OF ANSWERS:  I have added egreg's code snippets into this MWE to produce a document (and not just terminal output), showing the methods put forth to this point:  \documentclass{article}  %%%%%%%%%%%%%%%%%%%%%%%%%%%% L3 APPROACH  \usepackage{expl3}  \ExplSyntaxOn \cs_set_eq:NN \Xexplower \tl_expandable_lowercase:n \ExplSyntaxOff  %%%%%%%%%%%%%%%%%%%%%%%%%%%% EGREG'S LESS HACKY SOLUTION  \def\explowerchar#1{%   \ifcase\numexpr`#1-`A\relax    a\or b\or c\or d\or e\or f\or g\or h\or i\or j\or k\or l\or m\or    n\or o\or p\or q\or r\or s\or t\or u\or v\or w\or x\or y\or z\else    #1\fi }  \def\explower#1{%   \doexplowerchar#1\relax }  \def\doexplowerchar#1{%   \ifx#1\relax   \else     \explowerchar{#1}\expandafter\doexplowerchar   \fi }  %%%%%%%%%%%%%%%%%%%%%%%%%%%% STEVE'S HACKY PACKAGE APPROACH  \usepackage{stringstrings}  %%%%%%%%%%%%%%%%%%%%%%%%%%%%  \def\macros{Expandably converted an S to a s} \def\macrot{Expandably converted a T to a t}  \begin{document}  \textbf{Steve's hacky approach}  \caselower[q]{S}\csname macro\thestring\endcsname\par \caselower[q]{T}\csname macro\thestring\endcsname  \textbf{egreg's less hacky approach}  \edef\lcstring{\explowerchar{S}}\csname macro\lcstring\endcsname\par \edef\lcstring{\explower{T}}\csname macro\lcstring\endcsname  \textbf{L3 approach}  \edef\lcstring{\Xexplower{S}}\csname macro\lcstring\endcsname\par \edef\lcstring{\Xexplower{T}}\csname macro\lcstring\endcsname  \end{document} Possible Duplicate:          I have seen  in SQL. I wonder how would you approach the opposite problem: splitting coma delimited string into rows of data:  Lets say I have tables:  userTypedTags(userID,commaSeparatedTags) 'one entry per user tags(tagID,name)   And want to insert data into table  userTag(userID,tagID) 'multiple entries per user   Inspired by  question  EDIT  Thanks for the answers, actually more then one deserves to be accepted but I can only pick one, and the  with recursions seems pretty clean to me. It works on SQL Server 2005 and above.   For earlier version of SQL Server the solution  can be used.  For working with text data type  will be helpful. Thanks again. I'm using Drupal 7.  Is it possible to add a CC to a webform email?  I was using   function theme_webform_mail_headers($variables) {   $headers = array(     'X-Mailer' =&gt; 'Drupal Webform (PHP/' . phpversion() . ')',   );   return $headers; }   changing it with      function MYTHEME_webform_mail_headers($variables) {       $headers = array( 'CC' =&gt; 'ccmeail@domain.com', 'X-Mailer' =&gt; 'Drupal Webform (PHP/'. phpversion() .')',  );       return $headers;     }   It does not work, I've cleared all the chaches and it does not add the CC. How could I add the CC?  Thanks in advance. Closure of the set of degree $n$ polynomials with $n$ real roots A very beautiful (but maybe classic) exercise:   Consider the set $\Omega_n$ of polynomials of degree $n$ with real coefficients and $n$ distinct real roots.   What is the closure of $\Omega_n$ in $R_n[x]$?  ($R_n[x]$ denotes the set of polynomials with real coefficients of degree at most $n$)    The answer is the set of polynomials in $R_n[x]$ all of whose roots are real, plus the constant polynomials. Showing that this set is contained in the closure is not too hard, however the reverse implication is more difficult and I'm wondering what is the most elementary method to prove it (without talking about holomorphic functions for example). URL to create a new Google document What is the current URL to create a new Google Document please? Since Google last updated their Docs the old URL does not work. Story about a deadly alien creature on another planet that has some chemical in its body that makes it faster I can not remember if it was a short story or a novel, but I am leaning towards it being a novel. There is a colony of humans and I can't remember if they crash-landed or not.   There is a creature that they come to discover after it has killed a few people. The creature has some kind of chemical in its body that is like a super-adrenaline. One part is I remember is one of these creatures getting very hot from using up its reserve of this chemical and it dived into a river or pond and it started to steam. Something like that.  It has to be at least 10 years since I read the story. How to make a series of rectangles follow a pen path I am trying to get a series of shapes (rectangles) to follow a path (sine wave) that I made with the pen tool, but I have no clue how to do that or if it is possible.   I have tried warping a rectangle into the sine wave path, but it takes many different warped rectangles and it isn't smooth.  I thought  might work for rectangles, but it only works for text. equirectangular rendering for Blender Internal? Can such frames/videos be rendered in Blender Internal as well? If not, how indirectly?  EDIT: The below solution is great as long as you can write your own Python script and only render solid objects. When you need things like particles/hair, it won't work as those won't be reflected. When we define the S-matrix, what are "in" and "out" states? I have seen the scattering matrix defined using initial ("in") and final ("out") eigenstates of the free hamiltonian, with  $$\left| \vec{p}_1 \cdots \vec{p}_n \; \text{out} \right\rangle = S^{-1} \left| \vec{p}_1 \cdots \vec{p}_n \; \text{in} \right\rangle$$  so that  $$\left\langle \vec{p}_1 \cdots \vec{p}_n \; \text{out} \mid \vec{q}_1 \cdots \vec{q}_m \; \text{in} \right\rangle = \left\langle \vec{p}_1 \cdots \vec{p}_n \; \text{in} \mid S \mid \vec{q}_1 \cdots \vec{q}_m \; \text{in} \right\rangle.$$  1) What are "in" and "out" states?   2) Are they Fock states?   3) In Schrödinger or Heisenberg or interaction representation?   4) How are they related? (I believe that I see what they handwavily represent physically, but not formally.)  My main issue is that, if "in" and "out" states are one-particle eigenstates of the free hamiltonian, i.e. if $\left| \vec{p}_1 \text{out} \right\rangle$ describes a free particle with momentum $\vec{p}_1$, and $\left| \vec{p}_1 \text{in} \right\rangle$ also describes a free particle with momentum $\vec{p}_1$, then $\left| \vec{p}_1 \text{out} \right\rangle = \left| \vec{p}_1 \text{in} \right\rangle$ ... which is false. Still, books (some at least) describe these "in" and "out" states like that.  Moreover, I have seen (e.g. in Wikipedia, but also ) that the scattering matrix is a map between two different Fock states, and I don't understand that.   5) Do states of the interacting system live in the same Fock space that asymptotic free states?   6) And if not, where do they live?  Understandable references would be appreciated. In the United States, we say that someone lives on a street, whereas I've noticed that British people say in. For instance:     Bubba lives on Washington Street.   Colin lives in Cavendish Avenue.   I believe we both would use at when a number is given. For instance:     Bubba lives at 16 Washington Street.   Colin lives at 7 Cavendish Avenue.   I don't think it matters if it's a road, avenue, street, circle, or lane — as far as I know, in America, we always live on a street. Does it vary in British English, or is it always in? If it varies, what are the rules? Why do people risk death by joining Starfleet if not for money or preservation of their homes? Watching Star Trek made me think of a few "deeper" questions about Starfleet, which are all related to the Star Trek TV series.  So, let's take for example the Dominion War: people are dying every second, ships get destroyed and cadets are still joining although they know they are probably going to die unless they are with Picard or Sisko.  As I read and got to understand, money has no value anymore, latinum is the general trading currency in the universe. But people on Earth don't trade and don't earn their paychecks. Earth is a much better place than today and yet young boys and girls from every culture/civilization are joining Starfleet as they are willingly signing their death note.  Why are they joining, what motivates them? They might know that they're probably going to die.  They don’t earn paychecks. They could be doing any other job, yet they choose this. And what's more interesting how many died on battlefields must be lined up in front of StarFleet every day?  What do they receive after service? Why are they doing it other than preserving their homes? Accessing the index in 'for' loops? In the paper "Beautiful Code Compelling Evidence", by J.R. Heard -- Code is formated in a particular way which includes margin comments. I am looking for a way to do this as I think it is a very clear way to comment comment code in a literate programming style. It seems Microsoft has tried to solve this problem .  In Windows 7, there is no boundary between monitors and the mouse can move freely across the top of the screen between my 3 monitors, provided I had set their heights equal in display settings. Windows 8 introduced sticky corners. See .  Windows 10 got sticky corners as well. There are a few pixels at the top corners of each display where the mouse cannot cross over onto the other display. One must move the cursor down to avoid this region in order to get to the next display.  The image shows roughly the region where mouse movement is not permitted in Windows 10, but is allowed in Windows 7.    Personally, I had no problem with unrestricted mouse movement across the top of my screens - I got used to "aiming" for the x, and the convenience of unrestricted cursor movement. Like all the people who wanted to disable it in W8, I'm wondering if there is a way to disable it in W10.  Edit to address possible duplicate:  Although the problem is identical to the one in , solutions to solve the problem in W8 involving editing the registry key MouseCornerClipLength do not work in W10, since that registry key is not present in W10. Also adding that key and setting the value doesn't work. I searched the entire registry and couldn't find it in another location. No other W10 keys in the node referenced in the W8 solution are obvious replacements.  Edit to address possible solutions in comments  harrymc's  and  that worked for for Windows 8.1 do not work in Windows 10.