Could anyone explain x == !x is True? I have no idea about this crazy code.  const x = [0]; x == x // True. I understand this x == !x // True ???    I cannot understand what happen inside javascript and I need someone explain me this case.
Which equals operator (== vs ===) should be used in JavaScript comparisons? I'm using  to go through JavaScript, and it's returning many suggestions to replace == (two equals signs) with === (three equals signs) when doing things like comparing idSele_UNVEHtype.value.length == 0 inside of an if statement.  Is there a performance benefit to replacing == with ===?   Any performance improvement would be welcomed as many comparison operators exist.  If no type conversion takes place, would there be a performance gain over ==?
Setting items to status-completed before they're deployed In several scenarios, including two today ( and ), we have had bugs set to  simply because the fix has been checked in. Just because the code portion has been completed does not mean the work is done, and this can be confusing for users who come across the same problem. Until then it really is  or maybe a tag that doesn't yet exist (status-checked-in?).  Particularly in times like this week, where the stability of the system is a priority, I don't think this status should be set merely because the code has been checked in - it should happen when the code is actually deployed and verified. Currently the devs are being very good about telling us that the code is done but they're not sure when it will be deployed, but I think that is because of the stability issue. What are the advantages of 10-bit monitors? To support 10-bit color the following are needed:   A monitor supporting it. A GPU supporting it (only AMD FirePro and NVIDIA Quadro support this?). Compatible software. Unless I am mistaken there are very few programs out there supporting 10-bit color. Photoshop is a notable example.   The questions are about how 10-bit monitors perform in comparison with 8-bit monitors:   In which situations would a 10-bit monitor give a noticeable advantage over an 8-bit monitor (say, for professional photography)? Have 10-bit monitors been compared against 8-bit monitors based on subjective or objective tests? What were the results? Human eyes can see only 10m colors, so would using a monitor with 1b colors make a difference? Split Excel table over multiple PowerPoint slides I have a table in Excel which is too long for one PowerPoint slide. So I would like to split it over 2 or 3 slides, but have the header on each of the slides. What is the easiest way to accomplish that? I am using Excel and PowerPoint 2007. Blender is rendering an older version of my project, not the most recent one. I have made it using the Blender Render but it does not want to render in cycles either. A black and grey screen is rendered as if everything is transparent. Checked general camera, lighting and compute devises in case I messed something up but I can't find anything. All my textures and objects look normal, does anybody know what is wrong or what to check?  Ok added link: Solving 2-degree equations in 3 variables. We are given 3 equations: $x^2+\sqrt3 xy + y^2 = 25$ $y^2 + z^2 = 9$ $x^2 +xz+ z^2 = 16$. $x,y,z$ are positive real numbers. Then we have to find value of $xy + 2yz + \sqrt3 xz$. How to delete files from a folder using a list of file names in windows? i have a folder with 2K+ files in it, i need to delete around 200, i have a txt file with all the file names i need removed ordered in a list, how do i remove the specific files from the folder using the list? (OS is windows 7) Best way to specify whitespace in a String.Split operation I know this question is someway similar to  where they recommend using 404, but after reading  where they suggest to use 301 when changing site URLs (in the specific case was due to redesign/re factoring) I get a bit of confused and I hope someone could clarify for this specific example:   Let's say I have an eCommerce site, let's also say the final user inserted some interesting items in the site and the eCommerce webapp created the item pages at the URLs: http://...?id=20, http://...?id=30 etc. Now let's say some of these interesting items got many external links toward them from many other sites because some people found those items very interesting and linked to them. After some years the final user deletes those items, so obviously the pages and URLs http://...?id=20, http://...?id=30, etc. now do not exist anymore, but still many pages on the web are linking toward them.   What should the eCommerce site do now, just show a 404 page for those items?  But, I'm confused, wouldn't this lose all the Google PR passed by the external links to the items pages? So isn't it better to use 301 redirect to HOME PAGE that at least passes the PR to the HOME PAGE?    EDIT:  Well, according to answers the best thing to do so far is to do a 404/410.  In order to make this question more complete, I would like to talk about a special case, just to make sure I understood. properly.  Let's say the user creates those items again (the ones he previously deleted at point 4), maybe he changes a bit their names and description, but they are basically the same items. The webapp has no way to know these new added items were the old items so it obviously create them as new items with new URLs http://...?id=100, http://...?id=101, does it makes sense at this point to redirect 301 the old urls to the new ones?    ANOTHER EDIT (It would be VERY IMPORTANT TO UNDERSTAND):  Well according to the clever answers received so far it seems for the special case, explained in my last EDIT, I could use 301, since it's something of not deceptive cause basically the new pages is a replacement for the old page in term of contents. This is basically done to keep the PR passed from external link and also for better user experience.  But beside the user experience, that is debatable (*1), in order to preserve PR from external broken links why not just always use 301, In my understanding Google dislikes duplicated contents, but are we sure that 301 redirect to HOME PAGE is seen as duplicated contents for Google?!   Google itself  so if they consider 301 as duplicated contents wouldn't that be considered duplicated contents too? Why do they suggest it?  Let me provoke you: “why not just add a 301 to HOME PAGE for every not found page?”   (*1) as a user, when I follow a broken URL from some external link to some website's page I would stick more on this website if I get redirected to HOME PAGE rather than seeing a 404 page where I would think the website does not even exist anymore and maybe I don't even try to go to HOME PAGE of the website. How to split larger files into smaller parts? Distribution of $-\log X$ if $X$ is uniform. For $X$ and $Y$ random variables; $X$ follows the uniform distribution.  (1): if $Y=-\log X$  (2): then it can be shown that $-\log X$ is distributed as $\exp(1)$ {i.e. exponential with mean 1}.  Why is this so? Intuitively statement (2) make sense to me. But i'd like a mathematical proof.  -Probably wrong working:  (1) seems to imply $\exp(-Y) = X$ (which is like saying $X$ is exponentially distributed, which is a contradiction, since its actually uniform!); or is it incorrect for me to do this since $X$ and $Y$ are random variables?  Ultimately how do I prove (2)?  Thanks Why is polyploidy lethal for some organisms while for others is not? is the multiplication of number of chromosomal sets from 2n to 3n (triploidy), 4n (tetraploidy) and so on. It is quite common in plants, for example many crops like wheat or Brassica forms. It seems to be rarer in animals but still it is present among some amphibian species like Xenopus.  As I know in mammals polyploidy is lethal (I don't mean tissue - limited polyploidy). I understand that triploidy is harmful due to stronger influence of maternal or paternal epigenetic traits that cause abnormal development of placenta, but why there is no tetraploid mammals? I'm trying to fill empty space in my mesh, and I looked at the knife tool page on the Blender Wiki, and I'm not sure if there's a way to make it so that a new edge is made using the knife tool. I took a screenshot, and hopefully it'll explain better than I can of what I'm trying to do. Oh and I'm using Blender version 2.71, by the way. We sometimes buy trout from a local breeder who'll get them fresh out of the water for us, and then cook them a few hours later. They taste great, but the flesh tends to fall apart in a way that doesn't happen with fish from the super market. It's often barely even possible to get them out of the pot without them completely coming apart. We tried leaving them in the fridge for a day so they wouldn't be quite as just-killed-an-hour-ago-fresh, but that didn't help.   We usually prepare them by cooking them in simmering (not boiling) water.  Is there some way to prevent this? Does standard c library provides linked list etc. data structures? Prove that neither $A$ nor $B$ is divisible by $5$ Why didn't Elizabeth get cursed? In Pirates of the Caribbean, whoever has the Aztec gold gets cursed.  But Elizabeth had the gold coin with her which Bootstrap gave to his son Will before he was tied to a cannon and dropped to the ocean floor.  Barbossa states that they were cursed because of Aztec gold.  Also in the fight between Jack and Barbossa, Jack takes a gold coin and he was also cursed.  Why didn't Elizabeth get affected? Or was she also cursed and nobody noticed? C++: delete vs. free and performance It's often the case that I want to change name servers because my site is messed up.  Well, it takes a very long time for the name server to propagate.  Is there something in DNS, or registrar or anything I can do to speed that up.  Flushing my dns server using  and it rarely works Unable to locate package It just struck me that Utility Companies world-wide supply domestic users at either 50/60Hz. It could have been selected to be 10 Hz, or 100 Hz ... whatever  Was 50/60 chosen at random? Is there some rationale involved (efficiency, easier to construct/control etc) in restricting domestic supply to either 50/60 Hz?  In other words, if I were designing a power system, why would I pick 50/60 Hz instead of some other frequency?