skylanders traps

In C language, three-object operations are often used (cond? A: B). It is very concise, but this syntax is not supported in Python.However, it can be implemented using and or in Python (there is a trap here, which will be discussed below)Let's look at the following expressions:>>> False or 11>>> False or 00>>> True or 0True>>> True and 11>>> True and 00>>> False and 1FalseThat is to say, the and or expression returns a final expression result, instead of simply True or False. The following expre

The asynchronous mechanism of Node. JS is implemented by events and callback functions, which may feel like a violation of the routine, but the habit will find it very easy to get Started.There are, however, many pitfalls in This. A very easy problem to encounter is to go back to the callback function of the Loop.eqvar fs=require (' FS '); var files=[' a.txt ', ' b.txt ', ' c.txt '];for (var i=0;iThe results of the actual execution are as Follows:[' a.txt ', ' b.txt ', ' c.txt ']3undefined[' a.t

1. Reduce or avoid repaint, reflow; Repaint is to redraw the page, such as changing the text color, reflow change the structure, the overall can be understood to reduce the DOM operation.2. Cache the data as much as possible.3. Use CSS3 Transform instead of DOM operation.4. Do not add CSS3 animations to non-position:static. (Will multiply the browser overhead)5. Proper hardware acceleration. You can set TRANSFORM:TRANSLATA3D (0,0,0);.Performance Traps

a subclass, the subclass's double-underline method __private does not "overwrite" the parent class, but the _protected method of the subclass's single-underline method "Overrides" The parent class's method.The reason for this is that subclasses want to "overwrite" the method of the parent class so that the subclass can have access to the parent class's corresponding method.Do not define Python's obfuscation class method nameThe Python interpreter for a class (ClassName) Double-underlined privat

are reviewing again. 3.someLet arr=[' xzblogs ', ' Little Wise ', ' Zachary '];arr.some (x=>console.log (x));4.mapLet arr=[' xzblogs ', ' Little Wise ', ' Zachary '];console.log (arr.map (x= ' web ')); Map is a replacement here, and this is a follow-up course that will be explained in detail. Array conversion stringIn development we often encounter the output of the array into a string form, we learn two methods today, you should pay attention to the difference between the two methods.Join () m

When a decoration contract is signed, the project budget provided by the decoration company is an important part of the contract. A detailed review of the budget book is an effective way to prevent low-price traps of some bad companies. The review of the budget book for home decoration should start from the following aspects: Project Review: The budget documents provided by the home decoration company must be divided according to the functional area

I watched a video from Beijing wind network and summarized several typical Java traps for everyone. The answer is hidden. CTRL + A is displayed. We recommend that you first think about the results and then run the code test. Maybe you will suddenly realize. 1. Search for odd numbers: Public static Boolean isodd (int I) { Can the above method find all the odd numbers? A: The negative number is not taken into account. If the parameter is a negative numb

The code is as follows:LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"Android:layout_width= "Match_parent"Android:layout_height= "Match_parent"android:orientation= "vertical"> Tool Bar - includeLayout= "@layout/toolbar_main">include> Android.support.v4.widget.DrawerLayoutAndroid:id= "@+id/dl_alllayout"Android:layout_width= "Match_parent"Android:layout_height= "Match_parent"android:fitssystemwindows= "true"> The content *************** must be placed below

Inference for equal hexadecimal numbersExcuse me for example the following program output is God horse?#include Why is it not equal?See:Detailed reason: Literal constants also have default types, details such as the following Shaped literal constant (0xfe. 0x124,123,0) is of type int The type of the character literal constant (' 0 ', ' a ') is Char The type of Boolean literal constant (TRUE,FALSE) is bool The type of string literal ("ABC") is const char* Http://zhidao.b

Operating system: Windows ten ProCpu:amdIde:android Studio 2.0jdk:8.0After installing as (Android Studio), running as discovery fails to start the emulator, prompting "the Intel HAXM cannot be installed and your CPU does not support the required features (vt-x or SVM)." ”。 A pit.Had to install genymotion. Download is Genymotion-2.7.2-vbox (with vbox virtual machine), finally installed, run Genymotion, error is as follows:Can find the solution are found, toss half a day, no fruit. A second pit.No

1. Reduce or avoid repaint/page redraw, reflow/page reflowRepaint: Changes in style, such as colorReflow: The cost of change is greater than repaintCan also be understood as manipulation of DOM elements2. Try to cache all data that can be cached3. Use Css3transform instead of DOM operation, ANIMATE.CSSNon-mainstream performance optimization principles1. Do not add CSS animations to non-static positional elements (such as absolute,relative)2. Proper use of hardware accelerationA simple example of

First, Member operators number.prototype.testfn=function () { Console.log ( this this Span style= "color: #000000;" >.valueof ());} var num = -1;num.testfn (); // true-1 (). TESTFN (); // false 22.testFn (); // uncaught syntaxerror:invalid or unexpected token ( -1). TESTFN (); // true-1 -1..testfn (); // false 1 -1.2.testfn (); // false 1.2 The dot operator is prioritized as part of a numeric constant, and then is the object property accessor.Second, even equal assignment valu

1. There is a thread class object (implemented by inheriting the thread class), and if the program has never called the object's start () method to start it, then the thread object will always be in the "new" state, which is never an opportunity for the thread to execute, just a normal Java object, When calling its run () method directly, it is no different from ordinary methods of ordinary Java objects.2. static method by adding synchronized keyword to achieve synchronization, at this time the

, which is itself a list, we know that the list is mutable, so in Python, this list is a reference, only one copy in memory, so, change the list in Alist, List1 also change, finally demonstrated that the tuple in the list, the tuple itself is not mutable, so change the contents of the tuple will error, and pass the value, but this tuple as a list of elements, we can replace the whole.May say the more disorderly, oneself try to know, this is a "shallow copy" and "Deep copy" problem, shallow copy

For a long time did not write C + +, today wrote a very simple string class, unexpectedly debugging a half-day, finally found a very hidden trap, write out for everyone to share.The function of a copy constructor for a class in C + + is to instantiate another object from one object of the class. Here is a mystring class I wrote, the header file MyString.h:#include Take a look at the implementation version of the first class:#include use a simple example to test (test.cpp):#include "MyString.h" #

is used, the error will be directly, and the compilation will fail. (Children with unknown truth say that the error is because Goto is a C-language thing, using a goto must put the variable at the beginning of the function, it is clearly wishful thinking.) ）Finally, if you compile the debug version of the program, such problems can be quickly checked, according to my test, in the debug version, the VC compiler will generate the corresponding code for uninitialized variables to do the test, once

BindWhat results does the following code output?Class Foo {Constructor (name) {THIS.name = Name}Greet () {Console.log (' Hello, this is ', this.name)}Somethingasync () {Return Promise.resolve ()}Asyncgreet () {This.somethingasync (). Then (This.greet)}}New Foo (' dog '). Asyncgreet ()If you say the program will crash and error: cannot read property ' name ' of undefined.Because the Geet in line 16th is not executed in the right environment. Of course, there are many ways to solve this bug!I lik

(if you do not use multi-threading, you can do a batch of data or all succeed, and a failure is all rolled back).The code snippet is as follows:Code a Reclaimmatchsubscriptionserviceimpl,private void Savehistorymatches (final matchedinfoparams params, final commontaskname taskname, final Listpublic void Saveworkingtask (T params, commontaskname TaskName, taskpriority priority) {Assert.notnull (params, "Com Montaskparams must not being null "); Assert.notnull (TaskName, "commontask

Problem finding: The "local" variable inside the For loop, after an exception, the assigned variable still has a value to output.Each loop is output and no duplicates are found.Conclusion: There is no "local" variable in for.The variable scope within Python, the minimum is in the function unit.Above is the class, and then the module.For this problem, and the output is not duplicated, because an exception occurred after the assignment statement block, the output of the design is not good.The valu

c++| Chinese traps six. Virtual methods must be explicitly overloaded In C #, if a programmer decides to overload a virtual method, he or she must explicitly use the Override keyword. Let's examine the benefits of doing so. Assuming company a wrote a window class, Company B purchased a copy of the window class of company A as the base class. The programmer of Company B derives from the idea that ..., which is clearly derived from the following terms