advanced network devices

is an internal scope def F1 (): ... Print # This is F2 () is scoped def F2 (): ... ' Eric ' ... >>> F2 () AlexPython is a scoped chain (small knowledge point four)>>> name ='Alex'# This is F1 () is a scope, it is an internal scope>>>defF1 (): ...Print(name) ...#this is F2 () is a scope>>>defF2 (): ... name='Eric'... returnF1 ...>>> ret =F2 ()>>> ret ()#this is equivalent to running F1 ()AlexPython is a scoped chain (small knowledge point five) for Loop, then add 1 to ea

Specify Permissions GRANTS rights Table Operations Creating table Create tables Delete Table drop tables Clear Table Transcate Creating a temporary table create temporary table Automatic Incremental Auto INCREMENT Primary KEY PRIMARY Key FOREIGN Key FOREIGN Key Constraint CONSTRAINT ALTER TABLE Data manipulation New Data INSERT Deleting data Delete Updating Data Update WHERE JOIN GROUP by ORDER by INSERT

JAVA advanced-Network Programming> Connect to the server through a socketSocket refers to Socket> Read the homepage of any website--------- /** * @author Lean @date:2014-10-9 */public class SocketSample {public static void main(String[] args) {BufferedWriter writer=null;Socket socket=null;try {while (true) {try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}socket=new Socket("

the decryption key, which in turn is establishedAsymmetric algorithms : Symmetric cipher algorithms are sometimes called traditional cryptographic algorithms, that is, the encryption key can be deduced from the decryption key, in turn, also set upThere are many kinds of encryption algorithms, in iOS development, MD5 is our common digest algorithmTwo. MD5 encryptionHashing algorithm: A unique and extremely compact numeric representation of a piece of data. The hash value of the data can verify t

Plus () { SetTimeout (function() { console.log (' aaa ') },+) C +=1;} Plus () print ()AsynchronousEach task has multiple callback functions, and the previous task does not perform the next task, but instead executes the callback function, and the latter task executes in the order in which the task is sorted, not waiting for the previous task to complete// asynchronously executes the callback function after the task execution completes var c=0function print () { console.log

differences: Both Redis and Memcache store data in memory, both in-memory databases. But memcache can also be used to cache other things, examples, videos, and so on. Data type--memcache Specify the byte length of the data when adding data; Redis does not need to. Virtual Memory--redis When the physical memory is exhausted, you can swap some long-unused value to disk. LRU algorithm. Expiration policy--memcache is specified when set, such as set Key1 0 0 8, which never expir

=" 5e77f7febc844f91a443d168d01bd849.png "/>Step 9: After the target table is determined, we can choose an import mode, that is append or overwrite, after the selection is complete, the next step650) this.width=650; "src=" Https://s4.51cto.com/oss/201711/08/9a50d5770d8ccd7971736dee925436fc.png "style=" float: none; "title=" QQ picture 20171108143400.png "alt=" 9a50d5770d8ccd7971736dee925436fc.png "/>Step 10: Click to start, the following interface, pay attention to error or abnormal information.

Get this process id:os.getpid ()Get parent Process Id:os.getppid () fromMultiprocessingImportProcessImport TimeImportOSclassMyprocess (Process):#inherit the Process class def __init__(self, name): Super ().__init__() Self.name=namedefRun (self):#You must override the Run method Print('%s is running; the parent process ID is:%s'%(Os.getpid (), Os.getppid ())) Time.sleep (3) Print('%s is ending; the parent process ID is:%s'%(Os.getpid (), Os.getppid ()))if __name__=='__main__': P=

Network Debugging Tools Tcpdumpfunction : Print header information in the specified network interface that matches the Boolean expressionKey Words :① Type: Host (default), NET, port210.27. 48.2 // indicates that it is a host computer 202.0. 0.0 // indicates that a network at // indicate port number② confirm Transmission direction: SRC, DST

own downline, program exit"); System.exit (0);}} catch (IOException e) {//TODO auto-generated catch Blocke.printstacktrace ();}}}Execute the above code and run the result:Client output:Client: Multi-threaded ..... Hello, serverclient: Hello, serverserver: Hello, Clientserver:server send more than one message: server:1. Abcdserver: 2.1234Server: 3. Abcclient send multiple messages: Client:client send more than one message: 1. Xxxxxclient:1. Xxxxx2.yyyyclient:2.yyyy3.zzzzclient:3.zzzzbyeclient:

Table_namewhere column_name operator Valuegroup by column_name such as: Using GROUP The By statement groups the data table by name and counts how many records each person has:mysql> SELECT name, COUNT (*) from employee_tbl Group by name;+--------+---------- +| Name | COUNT (*) |+--------+----------+| Xiao Li | 1 | | Xiao Ming | 3 | | Xiao Wang | 2 |+--------+----------+3 rows in Set (0.01 sec)MySQL alter commandYou need to use the MySQL alter command when you modify the

When the primary process opens a child process, the master process executes in parallel with the child process. When the main process does not immediately end the process, but wait until the end of the child process to end, so as to clean up the zombie process (to the child process corpse).The first way:From multiprocessing import ProcessImport timedef task (name): Print ('%s is running '% name) Time.sleep (3) Print ('%s is do '% name)if __name__ = = ' __main__ ': p = Process (Target