advanced features

13. Thread PoolThe fourth way to get a thread: The thread pool, a executorservice, uses several possible pool threads to perform each submitted task, typically using the Executors factory method configuration.The thread pool resolves two different

SliceA slice is a partial element that gets a list, a tuple, a string, and so on1L = Range (100) 2 #take [0,5] element3 Print(L[:5])#[0, 1, 2, 3, 4]4 #in [0,99], take one of every 10 elements5 Print(L[::10])#[0, ten , +, +, +,--6 #take the last five

The first part walks into JavaPart two automatic memory management mechanismThe 2nd Chapter garbage collector and memory allocation policy1.Java virtual machine When executing a Java program, the memory that it locks into is divided into several

Format comparison:List imprehensions Format: [Statement for ...]Generator format: (Statement for.. In.. ）The difference: The list stores the specific content, each element occupies space, when the need to store n data, occupy a large spaceThe

In many languages, the function itself is allowed to be passed as a parameter to other parameters: the so-called higher order function. There are similar features in Python:First, map/reduce, filter, sortedThe idea of map-reduce in Hadoop has become

The first part walks into Java one, into Java1. OverviewJava is widely used in embedded systems, mobile terminals, enterprise servers, mainframe and other occasions, to get rid of the constraints of the hardware platform, to achieve the "write once,

Conversion between struct and map1 //struct2map convert struct to map2Func Struct2map (StInterface{}) map[string]Interface{} {3VT: =reflect. TypeOf (ST)4VV: =reflect. ValueOf (ST)5 vardata = Make (map[string]Interface{})6 forI: =0; I {7F: =

__slots__Magic In Python, each class has an instance property. By default, Python uses a dictionary to hold an instance property of an object. This is useful because it allows us to set any new properties at run time. However, for small

Generator *************In Python, this side loop calculates the mechanism, called the Generator (Generator), which saves a lot of space. List generation, which consumes memory when the element is printed when it is generated.One, two ways to read

Advanced FeaturesGeneratorThere are two ways to read generator elements :? G.next ()? for Loop read ; ( The generator is essentially an iterative object );? List-generated ( list generation is a very simple and powerful built-in Python build that

Iteration (Iteration)To judge an object to iterate:1. You can traverse through the for loop2. Judging by the iterable type of the collections moduleWhat if you want to implement subscript loops like Java for a list:Python's built-in enumeration

By mastering Python's data types, statements and functions, you can basically make a lot of useful programs.But in Python, not as much as the code, the more complex the better, the simpler the better.Based on this idea, some of the advanced features

This article illustrates the advanced features of JavaScript object-oriented programming. Share to everyone for your reference, specific as follows: 1. Three ways to create objects: The first method of construction: New Object var a = new

Redis Foundation, advanced features and performance tuning Kelgon attention 2017.02.28 16:22 words 12597 read 16333 comments 5 like 154 appreciate 2 This paper will start from the basic characteristics of redis, through the description of the REDIS

It can be combined with different programming languages such as PHP, JavaScript, ASP, ASP.net, ColdFusion, Java, and ABAP. FCK configuration and use are simple, but the default configuration does not meet all requirements, so we need to know some

1. CursorsPurpose: In the case of a lot of data, if the Java code in the loop after the update data, will cause frequent database connection, cost performance, so you can use the cursorRole: Queries come out of the collection directly in SQL to

1.oracle OptimizerThe goal of optimization is divided into 4 categories:Choose (optional)Rule (rules-based)First rows (line one)All rows (all rows)Description: Describe the execution plan for SQLObject owner: Objects SchemaObject Name: Objects

Oracle Database transactions1. Transaction definitionA transaction is a logical unit of work in a database,A transaction consists of one or more SQL statements that complete a set of related behaviors.The transaction mechanism ensures that the

First, synonym synonymConnect sys/123 as SYSDBA;SELECT * from EMP;ORA-00942: Table or view does not existCreate synonym emp for scott.emp;SELECT * from EMP;1. DefinitionA synonym is an alias for a pattern object.Can be a table or view, sequence,

Partition table:A partitioned table is a separate logical table that is implemented by multiple physical tables.The way MySQL implements partitioned tables is to encapsulate the underlying tables. This means that there is no global index, and the