What is the best way to handle different date formats in C# Dynamically with out hard coding Current culture info
Parsing DateTime on Localized Systems
Primes congruent to 1 mod 6 I came across a claim that I found interesting, but can't seem to prove for some reason. I have the feeling it should be easy  a prime $p$ can be written in the form $p = a^2 -ab +b^2$ for some $a,b\in\mathbb{Z}$ if and only if $p\equiv 1\bmod{6}$ I am using ArcMap 10.1. The background: I have an .mxd that I intend to roll out across the company as our default template for all future maps/figure production. This .mxd contains two Data Frames; the first (&quot;Main&quot;) is larger (occupying almost the entire page) and is designed to be used to hold the majority of mapped data whilst the second (&quot;Inset&quot;) is much smaller and is to be used as an overview map. The problem: When choosing to import this new .mxd to an existing .mxd (using the Change Layout button on the Layout toolbar) the wizard automatically selects the smaller (&quot;Inset&quot;) Data Frame to occupy the larger part of the page. The screenshot below shows this interface with a red box indicating the two possible locations of each Data Frame:  Whilst it is possible to manually alter the order of the Data Frames using the Move Up or Move Down buttons, how do I change the default option for this setting (i.e. so that the &quot;Main&quot; Data Frame always appears in the larger space - &quot;2&quot;)? The reasoning is that I would like the process of using this new .mxd template to be as simple as possible, this is especially important as we have a wide range of users with varying abilities. Does anyone know how to choose/change this default setting? It does not appear to be in the Data Frame Properties &gt; Data Frame menu where I would expect it to be. Cannot update/get any packages. gedit not installed my problem is that my sources.list is out of date for some reason. I already found the fix in another port, but it doesn't work. It says to use gedit to edit sources.list and replace everything with the proper sources. Well, for some reason I don't have it installed (Ubuntu Server 14.04) and I can't install it or else I get the main problem again.  Failed to fetch http:// some ubuntu site Could not resolve hostname "us.archive.ubuntu.com"  Is there any other way to edit sources.list? Or do I need to do a re-install of the OS? File Upload using Selenium WebDriver and Java Robot Class What is the cardinality of the set of the empty set? Hello,    This question is about the Command Line Developer Tools that are usually installed with xcode-select --install and updated via a software update from the Mac App Store (at least until macOS 10.13). I use the developer toolchain on a daily basis and it has always worked and updated without issues.    Today I've updated my mac from High Sierra 10.13.6 to Mojave 10.14.1, and I've lost the ability to update the Developer Tools.    After the update I've executed a terminal command that relies on the developer tools being installed. It was a command to update , although I don't think that the specifics matter, as I believe that any task that tried to access the developer tools would have triggered the same error message.    The error was:   xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun       The phrasing was new (maybe), but I thought that it was caused by the usual need to re-install the Developer Tools after some macOS updates.    Later I tried to dig a bit deeper into the failure, and found out that:  $ ls -l /Library/Developer/CommandLineTools/usr/total 0drwxr-xr-x  3 root  admin  96  4 Nov 19:32 share$ which xcrun/usr/bin/xcrun$ xcode-select -p/Library/Developer/CommandLineTools    Still, as I normally do, I entered the command to install and update the Developer Tools in the terminal:  xcode-select --install    This started the usual procedure: modal window to confirm, then request to accept the license agreement, followed by a progress bar. Except that it failed very quickly with an unexpected error:     Can&rsquo;t install the software because it is not currently available from the Software Update server.     I've tried several times, to no avail. It gets always stuck.    Sometimes, however, the failure causes the System Preferences to report a pending update:      If I open that preference panel it starts searching for updates, and it always finds nothing except the first time that it happened. The first time, it found this:          It literally suggested me to install the updates for macOS 10.11 and 10.13. I have no idea why.  I closed the preference without installing, and as I said it hasn't shown them again. There is also no update available in new Mac App Store.   Is this a known issue? Is there any way to resolve the problem?     Update  Of course I can download the Dev Tools for macOS 10.14 installer from .  Before installing them manually, though, I'm wondering if there is anything that's broken with the system. Challenges with Key with Gaps? I had a mistake with a trigger which resulted in errors in PostgreSQL 9.4.3 on x86_64-unknown-linux-gnu, compiled by gcc (Debian 4.9.2-10) 4.9.2, 64-bit.  Each time during the error, the primary key of SERIAL increased.  After fixing the bug, the table measurements is    measurement_id | measurement_size_in_bytes |             time               ----------------+---------------------------+-------------------------------               1 |                     77777 | 2015-07-14 18:29:56.858703+03               2 |                       888 | 2015-07-14 18:29:56.882552+03               3 |                       888 | 2015-07-14 18:30:15.505957+03               4 |                       888 | 2015-07-14 18:41:01.878106+03              39 |                     77777 | 2015-07-15 12:11:21.21391+03              40 |                     77777 | 2015-07-15 12:11:59.551973+03              41 |                     77777 | 2015-07-15 12:12:05.48982+03              42 |                     77777 | 2015-07-15 12:13:02.402053+03              43 |                     77777 | 2015-07-15 12:13:02.419412+03              44 |                       888 | 2015-07-15 12:13:02.434728+03          ...   where the amount of error statements has been 35 (= 39-4).  This jump in IDs may become a challenge later when I want to integrate this table with a partial index where order matters.   Table  CREATE TABLE measurements     (         measurement_id SERIAL PRIMARY KEY NOT NULL,         measurement_size_in_bytes INTEGER NOT NULL,         time TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,         CONSTRAINT no_duplicate_measurements UNIQUE (time)     );       What are the challenges of keys with gaps? How to define a bijection between $(0,1)$ and $(0,1]$?   Or any other open and closed intervals?   If the intervals are both open like $(-1,2)\text{ and }(-5,4)$ I do a cheap trick (don't know if that's how you're supposed to do it): I make a function $f : (-1, 2)\rightarrow (-5, 4)$ of the form $f(x)=mx+b$ by \begin{align*} -5 = f(-1) &amp;= m(-1)+b \\ 4 = f(2) &amp;= m(2) + b \end{align*} Solving for $m$ and $b$ I find $m=3\text{ and }b=-2$ so then $f(x)=3x-2.$  Then I show that $f$ is a bijection by showing that it is injective and surjective. Negative Mass and gravitation Using modulo operation to draw graph Was Severus Snape made a Death Eater before or after he told Voldemort about the Prophecy? Based on discussion in comments on , was Severus Snape a Death Eater (real one, with Dark Mark) before he overheard Sybil give the Prophecy to Dumbledore and relayed it to Voldemort? Or was he made a DE after that?  Canon sources only please (books/interviews/Pottermore) Does it look good to edit the question you're answering? I have a question about editing practices:  Does it look good to edit a question you have just answered?  For example: say I had just answered a question, then saw that the question had some minor formatting issues. Should I edit it? Does it turn up voters off when they see that I am answering a question I changed, possibly to better suit my answer? What is the name of the character $\wp$? What is the name of the character whose code is $\wp$ ?  Thanks I thought this would be really simple, but it's presenting some difficulties. If I have std::string name = &quot;John&quot;; int age = 21;  How do I combine them to get a single string &quot;John21&quot;? We often see new users make offtopic, low quality posts, with broken English and cries for help. These questions look significantly different from most on SO.  When I worked in publishing, we would frequently receive documents that were incorrectly formatted. This was a major problem and we wasted a lot of time sending emails back and forth.  I made a small JavaScript quiz asking our authors about the formatting directions and the number of emails drastically dropped. I felt this was much nicer than simply rejecting them, additionally providing us a chance to make the directions more clear.  It is slightly unconventional but, would showing new users a quiz where they have to identify good and bad posts help to improve the quality of SO questions?  Edit (3/8/2017)  Recently a Norwegian website got some media attention for . Cross-validation for timeseries data with regression What does this phrase from The adventures of Tom Sawyer sentence mean: "True, the knife would not cut anything, but it was a "sure-enough" Barlow, and there was inconceivable grandeur in that -- though where the Western boys ever got the idea that such a weapon could possibly be counterfeited to its injury is an imposing mystery and will always remain so, perhaps."  Thank you! Intel® Core™2 Duo Processor E4300 - Is it a 64 Bit Processor? I have a PC with an Intel® Core™2 Duo Processor E4300 - I ran CPU-ID on it, and here are the results:    Is this capable of running Windows 64-bit? What does it mean when it says under a journal article that it has been communicated by "XYZ" where XYZ is not the author but some other scholar with a very strong reputation? What is the relationship to the actual author and/or the content? Is this some sort of seal of approval to get results out and known quickly? (I am specifically wondering in the context of mathematics and mathematical physics.) MySQL cartesian product between two SELECT statements