advanced security concepts

()), and then compare the result to the rule above.4, any number and Nan compare return false.Equality operatorsequals sign (= =) does not equal (! =) Convert the operands first, and then compare their equality.Congruent (= = =) Not congruent (!) = =) does not convert operands, directly compared.A===b must have a==b, and a!=b must have a!==b.Conditional operatorVariable = boolean_expression? True_value:false_value;The expression is based on conditionally assigning a value to a variable accordin

loop;Continue resumes from the top of the loop after exiting the loop1.5.7 Switch statementswitch (expression): {Case value1:StatementBreakCase Value:2StatementBreakDefaultStatement}1.5.8 with statementsThe function of the WITH statement is to set the scope of the code to a specific objectWith (expression) statement;1.5.9 Label StatementUse the Label statement to add tags to your code for future useLabel:statement;1.6 Functions(1). Disclaimerfunction functionname (arg0,arg1,arg2,..., ArgN) {Sta

First, underfined and null1. When declaring a variable using VAR, but not initializing it, the value of this variable is underfinedA 2.null value represents an empty object pointer, and if the defined variable is used in the future to hold the variable, it is better to initialize the variable to null instead of the other valueThe 3.underfined value is derived from null so alert (null==underfined)//trueTwo, Boolean type1.Boolean only two literal literals can only be written as true, False and not

is especially useful for reading and writing less data access scenarios.Iv. Summary1, Concurrenthashmap and copyonwritearraylist are non-locking reads, so the read operation does not ensure that all other threads are currently written, not for scenarios that require strong data consistency.2, Concurrenthashmap and copyonwritearraylist can ensure that the read can be aware of the completed write operation.3. CONCURRENTHASHMAP read operations may perceive the intermediate state of the container w

, except for the left 1 of the decimal point), exponent 4 (binary shift code 00000000010), sign bit 0 = = Computer Storage: 0 00000000100 10011001100110011 ... 11001 = = Because the mantissa is up to 52 bits, the actual stored value is 0.00011001100110011001100110011001100110011001100110011001 and the decimal 0.2 = = Binary 0.0011001100110011 ... (Cycle 0011) = = Mantissa is 1.1001100110011001100 ... 1100 (total 52 digits, except for the left 1 of the decimal point), exponent 3 (binary shif

1. Anonymous functions Anonymous functions (anonymous function) are functions that are not bound to any identifiers, and are used in functional programming languages fields, typically: 1) passed as a parameter to the higher order function (Higher-order function), such as built-in functions in Python filter/map/reduce are typical high-order functions 2) as the return value of the higher order function (although the "value" here is actually a function object) In contrast to a named function (named

IOS advanced learning-Network-based data security, ios advanced I. Data Security 　　 1. terms: Key: A key is a parameter entered in an algorithm that converts plaintext to ciphertext or converts ciphertext to plaintext. Keys are classified into symmetric keys and asymmetric keys (you can also divide them into encrypti

favorite word is "everything has the price". Any performance gains we get through indexing are not without a price. The cost comes from several aspects.1. The principle of the clustered index we know that when the table is indexed, the data is stored as a B-tree. So when the update is inserted and deleted, it is necessary to move the page physically to adjust the B-tree. Therefore, when the update is inserted to delete data, it can degrade performance. For clustered indexes, when the table is u

One, JavaScript composition1. A finished javascript is composed of three parts: ECMAScript, DOM, and BOM.ECMAScript: Provides core language functions-grammar, type, statement, keyword, reserved word, operator, object;DOM: Document Object Model-provides methods and interfaces for accessing and manipulating Web page content;BOM: Browser Object Model--provides methods and interfaces for interacting with the browserSecond, reference JS in the page1. There are two ways to refer to JS in a Web page--E

First, MAVEN integrates eclipseMaven is very good, but it's not always nice to have command-line knocks, we're used to using the IDE, so there's a way to integrate Maven into eclipse.View more:http://www.eclipse.org/m2e/,http://download.eclipse.org/technology/m2e/releasesThe latter is also the updated address of the plugin, which will restart eclipse after installation, and then set up several maven plugins:To find Window->preferences->maven, two places need to be modified:　　　　Two　　"Java EE Lear

Object-oriented (advanced)-basic concepts of interfaces An interface is the most important concept. An interface can be understood as a special class, which is composed of global constants and public abstract methods.Interface Definition Format: Interface interface name {Global constant;Abstract method;} Interface Definition: Interface {Public static final string author = "James ";Public abstract void print

Equality operators: 　　Equal = =: This operator converts the operands first, forces the type conversions, and then compares their equality. 　　　　 null = = undefined //truenan = = Nan //False"5" = = 5 //true Congruent = = =: Congruent does not occur when a forced type transition occurs, and the type is compared. "5" = = = 5 // falseNull = = undefined //false 　　 Conditional operatorvarible = boolean_expression? T

the number is turned out, if there are characters, turn out Nan. If it is empty, turn out 0.The Parsenint () function has the following transformations: see if the first character is a number to decide whether to go out. For the problem of the binary, provide the second parameter is the binary number.The Parsenfloat () function has the following transformations: It only applies to decimal when it is converted, so the hexadecimal data is turned out 0.3) The length of any one string can be output

1. Local variables cannot be added with access modifiers, and member variables can.The 2.static class property, which is not owned by the object, is shared by all objects. Use the class name as much as possible to invoke the Class property instead of the object name.3. The class itself also has access modifiers, but the access modifiers for the class have only two of the common and default (no access modifiers). Classes that are accessed by default can only be used by other classes in the same p

1. Multiplicative operators:1) * Method of operation:Infinity * 0 = NaN Infinity * Not 0 = Infinity or-Infinity2)/method operator:infinity/infinity = Nan 0/0 = nan n0/0 = Infinity2. Relational operators:3. Conditional operators, assignment operators, comma operators, and so on.4. Statement:If,do-wihle,while,for,for-in,with,break,continue,label.5. Functions:1) Understand parameters: any parameters in the function are actually stored in the arguements[] array.2) without overloading, it will perfor

for-in statementsThe for-in statement is an iterative statement used to enumerate object properties, Syntax:For (property in expression) statementInstance:for (var propname in window) {document.write (propname);}Understanding ParametersThe ECMAScript function parameter does not mind passing in how many parameters, the defined function receives 2 parameters, but the call does not necessarily pass 2 parameters, can be more than a fewIn the body of the function, this array of parameters is accessed

-point format, it is converted to the corresponding floating-point format, ignoring leading zeros.If the string contains a valid 16 binary, it is converted to a decimal integer value of the same size.If the string is empty, it is converted to 0.If the string contains characters other than the above format, it is converted to Nan.If object: Call the ValueOf () method, and then convert the return value according to the previous rule. If the result of the conversion is Nan, the ToString () method i

Java inheritance, knowledge points of Advanced Concepts of classes, and java knowledge points 1.Inheritance In object-oriented programming, you can create a new class by extending an existing class and inheriting its attributes and behaviors. This method is called inheritance ). 2.Benefits A. code reusability B. Subclass can extend attributes and methods of the parent class. C. attributes and methods of the

Introduction to some advanced concepts of URL view functions in Django, djangourl view Functions Speaking of the branch of the Request Method, let's take a look at what good methods can be used to implement it. Consider the URLconf/view Design: # urls.pyfrom django.conf.urls.defaults import *from mysite import viewsurlpatterns = patterns('', # ... (r'^somepage/$', views.some_page), # ...)# views.pyfrom d

statement.A function that does not specify a return value returns a special undefined value.Either the function always returns a value or never returns a value. Otherwise, the function sometimes returns a value and sometimes does not return a value, which can be inconvenient for debugging code.Parameters:Ecmascipt doesn't mind passing in the number of arguments, and doesn't care what data type the parameter is. These parameters can also be accessed through the arguments object.Named parameters