mean

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: As from subject. I saw this terminology in a question I recently asked, and apparently it's a well established term, but I am not able to find anything on stackoverflow. 回答1: There are fundamental types and compound types. Fundamental types are the arithmetic types, void , and std::nullptr_t . Compound types are arrays, functions, pointers, references, classes, unions, enumerations, and pointers to non-static members. A cv-unqualified type is any of those types. For any cv-unqualified type, there are three corresponding cv-qualified types:

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: This question already has an answer here: What are Extension Methods? 8 answers namespace System.Web.Mvc.Html { // Summary: // Represents support for HTML in an application. public static class FormExtensions { public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName); ... } } I have noticed that 'this' object in front of the first parameter in BeginForm method doesn't seem to be accepted as a parameter. Looks like in real BeginForm methods functions as: BeginForm(string actionName, string

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have heard that applying display:none to things that are not visible is more accessible then changing opacity. However using display:none messes up some of my css animations that are progressively layered onto the core functionality. Is it accessible if in my css the element is hidden with opacity:0 and give the element the aria-hidden=true role, or should the element also have display:none ? Another factor to be considered is the aria roles are controlled by javascript (the css has a :hover pseudo-class fallback) in this instance. So for

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have the following dataframe: date id cars 2012 1 4 2013 1 6 2014 1 NaN 2012 2 10 2013 2 20 2014 2 NaN Now, I want to get the mean of cars over the years for each id ignoring the NaN's. The result should be like this: date id cars result 2012 1 4 5 2013 1 6 5 2014 1 NaN 5 2012 2 10 15 2013 2 20 15 2014 2 NaN 15 I have the following command: df["result"]=df.groupby("id")["cars"].mean() The command runs without errors, but the result column only has NaN's. What did I do wrong? 回答1: Use transform , this returns a series the same size as the

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have seen a method like shown below: protected T save( T Acd, boolean en) { What does it do? What is these type of method declarations called in Java? 回答1: It is called a generic method. This whole concept is called "Generics" in Java. That declaration means T can be any type that is subclass of ABC. 回答2: Bounded Type Parameters: There may be times when you'll want to restrict the kinds of types that are allowed to be passed to a type parameter. For example, a method that operates on numbers might only want to accept instances of Number or

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I know this is similar to another SO question , but the variable prime is supposed to be any number other than 1 , and it looks to me like it would be assigned the boolean value of num != 1 . Can anyone tell me what this line of code is actually doing? Here's the code where it's being used function isPrime( num ) { var prime = num != 1; // Everything but 1 can be prime for ( var i = 2; i < num; i++ ) { if ( num % i == 0 ) { prime = false; break; } } return prime; } EDIT: I assume that this line does something like this: if( num != 1) { prime

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: I have a large correlation matrix in a pandas python DataFrame: df (342, 342). How do I take the mean, sd, etc. of all of the numbers in the upper triangle not including the 1's along the diagonal? Thank you. 回答1: Another potential one line answer: In [ 1 ]: corr Out [ 1 ]: a b c d e a 1.000000 0.022246 0.018614 0.022592 0.008520 b 0.022246 1.000000 0.033029 0.049714 - 0.008243 c 0.018614 0.033029 1.000000 - 0.016244 0.049010 d 0.022592 0.049714 - 0.016244 1.000000 - 0.015428 e 0.008520 - 0.008243 0.049010 - 0.015428 1.000000 In [

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: am trying to calculate mean and variance using 3X3 window over image(hXw) in opencv...here is my code...is there any accuracy issues with this??or is there any other efficient method to do it in one pass.? int pi,a,b; for(i=1;i<h-1;i++) { for(j=1;j<w-1;j++) { int sq=0,sum=0; double mean=0; double var=0; for(a=-1;a<=1;a++) { for(b=-1;b<=1;b++) { pi=data[(i+a)*step+(j+b)]; sq=pi*pi; sum=sum+sq; mean=mean+pi; } } mean=mean/9; double soa=mean*mean;//square of average double aos=sum/9;//mean of squares double var=aos-soa;//variance } } 回答1: With

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm writing a Uno game in Python and I'm currently setting up a Uno deck. _VALID_FACES = ['skip', 'draw2', 'reverse', 'wild', 'wild4'] + range(10) I think this should be just fine and dandy, no problem. However, PyCharm insists on this error: Expected type list[str] (matched generic type 'list[T]'), got 'list[int]' instead Now I'm not entirely sure what this means. Any ideas? The code runs, but the warning is still there in PyCharm. 回答1: Though you can have list of strings and ints in python, it's preferable to keep list elements' types

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: What does it mean to double license code? I can't just put both licenses in the source files. That would mean that I mandate users to follow the rules of both of them, but the licenses will probably be contradictory (otherwise there'd be no reason to double license). I guess this is something like in cryptographic chaining, cipher = crypt_2(crypt_1(clear)) (generally) means, that cipher is neither the output of crypt_2 on clear nor the output of crypt_1 on clear . It's the output of the composition. Likewise, in double-licensing,