python learning 11: detailed explanation of Python tuple

Tuples are another important sequence structure in Python. Similar to lists, tuples are also composed of a series of elements sorted in a specific order. Unlike a list, a list can operate on any element and is a variable sequence, while a tuple is an immutable sequence, that is, the elements in the tuple cannot be modified separately. Tuples c ...

Posted on Thu, 17 Oct 2019 01:52:01 -0400 by manishdugar

The button driver written in pure C language separates the button logic from the button processing event~

button drive A key driver written by Jay himself supports single double click, continuous press and long press; callback is used to handle key events (custom buffeting time), which only takes three steps to create keys, link mapping between key events and callback processing functions, and periodic check of keys. Source address: https://github. ...

Posted on Wed, 16 Oct 2019 13:32:34 -0400 by kevin_newbie

C + + construction and parsing JSON

JSON is a lightweight data interaction format, easy for people to read and write, but also easy for machine analysis and generation, and effectively improve the efficiency of network transmission. It is often used in practical projects. Compared with xml, JSON has many advantages, such as asking duniang, a lot of advantages. Third party Library ...

Posted on Wed, 16 Oct 2019 10:41:39 -0400 by townclown

C language of MQTT client based on mosquitto

In the process of learning MQTT, the following contents help me https://www.runoob.com/w3cnote/mqtt-intro.html is a basic introduction to MQTT Https://mosquito.org/api/files/mosquito-h.html this website records almost all the mosquito interfaces you want to know. They all have function profiles. Maybe they can't see any points. Look at the deta ...

Posted on Wed, 16 Oct 2019 06:43:44 -0400 by zoooj

One of the design modes: single instance mode [creation mode]

The creation mode is divided into the following types. Singleton mode: a class can only generate one instance. The class provides a global access point for external access to the instance. Its extension is the limited multiple instance mode. Prototype pattern: an object is used as a prototype, and multiple new instances similar to the proto ...

Posted on Wed, 16 Oct 2019 05:57:11 -0400 by suigion

Deployment of load balancer in k8s

In Kubernetes, the IP address of the service and Pod can only be used inside the cluster network, and it is not visible for applications outside the cluster. In order to enable external applications to access the services in the cluster, the following schemes are provided in Kubernetes: NodePort LoadBalancer Ingress This section mainly introd ...

Posted on Tue, 15 Oct 2019 22:41:02 -0400 by mjm7867

ACL access control list -- standard access control list (Theory + Practice)

Overview of ACL (access control list) Access control list is a list of instructions applied to the router interface, which are used to tell the router which packets can be received and which packets need to be rejected. Access control is the main strategy of network security prevention and protection. Its main task is to ensure that netwo ...

Posted on Tue, 15 Oct 2019 15:35:21 -0400 by trdesigns

Build extended ACL practice

The topology of this experiment is as follows: Objective: Complete the establishment of extended ACL on R1 route, and achieve the experimental requirements: Allow PC1 to access Linux web services; Allow PC2 to access the ftp service of Linux; PC1 and PC2 are forbidden to access other Linux services; Allow PC1 to connect PC2 Experimental st ...

Posted on Tue, 15 Oct 2019 12:55:53 -0400 by nike121

ovn implementation of container Internet access, nat, fip

Experimental topology Physical topology Logical topology 172.24.4.8 is the fip of pod 100.60.0.31. step Get ready Create logical router ovn cluster ovn-nbctl lr-add ovn-cluster ovn-nbctl lrp-add ovn-cluster ovn-cluster-fip-ns1 00:00:00:65:77:09 100.69.0.1/16 Create logical switch fip-ns1 and connect to ovn cluster ovn-nbctl ls-add fip-ns1 ovn ...

Posted on Tue, 15 Oct 2019 12:32:02 -0400 by Xorandnotor

52 Effective Methods - Enumeration for State, Options, State Code

Enumeration (enum) Enumerations (enums) are just a way of naming constants. It is a basic data type in C language and a set of named integer constants. The specification defines "constants" such as states, options, and so on in the code. Does not participate in memory occupation and release. The purpose of using enumeration in develo ...

Posted on Tue, 15 Oct 2019 05:42:02 -0400 by puzzle