java 8 functional programming

First, higher order function1. Variables can point to functionsFor example, Python's built-in absolute value function abs ():f=ABSprint(f (-10))The output is 10.2, function name is also variableAny function name is a variable, and if it is assigned, it can no longer be used for function calls:abs=10Print(ABS ( -8)) #abs points to 10, can no longer use ABS () to call the function, will errorNote: Because the abs function is actually defined in impor

=true) key: How to handle each element reverse: Reverse sort #[8, 6, 3,-2, 1,-1, 0] Anonymous FunctionsLambda: anonymous function keyword: The preceding element represents the parameter of an anonymous function anonymous function without thanking the return expression, the return value is the value of the expressionm = List (map (Lambda x:x*x,[1,2,3,4))print(m) #[1, 4, 9, +]Decorative Device: Dynamically increasing functionality during code run#a

name returned inside the adorner, and to avoid some code execution errors that depend on the function name, the python built-in Functools.wraps can be used:ImportFunctoolsdeflog (func): @functools. Wraps (func)defWrapper (*args,**kw):Print('Call %s:'% func.__name__) returnFunc (*args,**kw)returnWrapper@logdefAdd (A, b):returnA +bPrint(Add (3,9))Print(Add.__name__)Practice:#Please design a decorator, which can be used on any function, and print the execution time of the function:#-*-codin

also a high-order function built into Python. The reduce () function receives a parameter similar to map (), a function f, a list, but behaves differently from map (), and reduce () the incoming function f must receive two parameters, and reduce () calls function f repeatedly on each element of the list and returns the final result value.The Python3 is placed in the Fucntools module with the first introduction: From Functools import reducedef f (x, Y):return x + yReduce (f, [1, 3, 5, 7, 9]) sum

and falls to the else part 'Third, lambda expressionFor simple functions, there is also an easy way to represent a lambda expression# ###################### Common function ###################### # defining functions (normal way) def func (ARG): return arg + 1 # execution function result = func (123) # ########## ############ Lambda ###################### # definition function (lambda expression)Lambda arg : Arg + 1 # execution function result = MY_LAMBDA (123)Iv. built-in f

,'5'75A'5'75A'6': 6,'7': 7,'8': 8,'9': 9} returnMydic[char]#2. Define the function parameters of the integer section reducedefMyfunca (A, b):returna*10+b#3. Convert an integer string to an integer value by Reduce/mapdefFunca (Strx):returnReduce (myfunca,list (Map (strtonumbera,list (STRX) ))#handle conversion of fractional parts#1, define the function parameters of the small part of reducedefMYFUNCB (A,

of the sequence in a cumulative way, with the effect of:Reduce (f, [X1, x2, X3, x4]) = f (f (f (x1, x2), x3), x4)Using reduce to achieve sequence summation from Import # use the Reduce function first import>>> l=list (range 1,11)>>> reduce (lambda x,y:x+ y,l) 55Using the reduce implementation to turn an integer sequence into an integer>>> l=list (Range (1,10))>>> reduce (lambda x,y:x*10+y,l)123456789Using reduce + map to implement the function of STR to int>>>defChar_num (c): ... digits={'0'70A

dynamically generates a parameter multiplied by 10type (TIMES10)#>>> TIMES10 (5)# -times5= Times (5)#a function that dynamically generates a parameter multiplied by 10TIMES5 (5)# -# # anonymous function: Lambda () function-Lambda functions are anonymous functions expressed in a single statement, which can be used instead of short functionsSyntaxLambda parameter: return valueLambdaEquivalent:def double (x): return x * 2-Previous high-order functions can also be passed directly using lambda a

parallelSort, Java 8 still uses the Fork-Join mode. The effect on small data volumes is not good because it takes some time to start the thread. I personally think that Java 8 is better at making concurrent/non-concurrent judgments for the Arrays. sort () interface. After all, if multiple cores are hidden from

Java 8 Functional InterfaceA functional interface (functional Interface) is an interface that has and has only one abstract method, but can have multiple non-abstract methods.A functional interface can be implicitly converted to a

New Features of Java 8 and new features of Java 8 1. Interface Improvement A. Static methods can be defined in the interface B. More importantly, the method in the interface can be modified with default to add the method body. 2. Why cannot I use the default method to override the equals, hashcode, and toString methods

does not have a standard action interface, and some articles say you can replace it with runnable, but Runnable is run on the thread, and we construct a Java interface function here 1 @FunctionalInterface 2 Public Interface Action {3 void 4 default action Andthen (action after) {5 Objects.requirenonnull (after); 6 return (), {accept (); After.accept ();}; 7 }8 }Constructing

' function, respectively, by invoking the method in the integer package to implement the binary, octal conversion, ' Help ' menu bar ' usage ' prompt dialog box.5. The entire program dialog can be minimized, maximized, and closed.Second, the experimental conditions1.PC Machine One set2.java Software Development EnvironmentThird, the experimental stepsA, division of labor Arrangements:In this experiment, when I initially identified the project, Daismi

This semester is almost over, and a variety of assignments are coming --! There are two major troubles: large jobs in C # And. NET and Java programming, which require a strong labor force. I am not good at. Net (I have been using Linux). The topic is to develop a LAN chat system. One of the teams in the same group is mainly responsible for this development: Http://blog.csdn.net/zyofprogrammer I am mainly re

take a look at the main features of Java SE 8 and start the programming journey on our favorite IDE.2. Introduction to Java SE 8 key features, big changesJSR 337 Overview: Java SE 8 Pu

its object, in this way, we pass some function functions to the Addmouselistener method. In short, it's not easy to pass a normal method or function as a parameter in Java, and Java 8 adds a new language-level feature called a Lambda expression . Why does Java need a LAMBDA expression? If you neg

8 Steps to learn Java, easy monthly entry of over, 8 Steps java monthly entry Java, as a general programming language, can do a lot of things, but it depends on how to learn Java. Many

: Network Disk DownloadContent Introduction······This book provides a comprehensive overview of the new features of the milestone version of Java 8, including lambdas, streaming, and functional programming. With functional programming