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Expression Expression is a sequence of operator s and operand s >>> 1 + 1 2 >>> a = [1,2,3] >>> 1 + 1 + 1 + 1 4 >>> 1 + 2 * 3 7 >>> 1 * 2 + 3 5 >>> a = 1 + 2 * 3 >>> a = 1 >>> b = 2 >>> c = a and b or c >>> c = int('1') + 2 Operator priority For example ...

In mobile application development, we sometimes need to monitor the time-consuming of some processes, such as application startup time, page Jump time, etc., which is not accurate only by naked eyes. We can realize it in several ways. One way is to obtain startup time by shell, one way is to output time by code point tapping, an ...

Lifecycle: official introduction Lifecycle is a class that holds the information about the lifecycle state of a component (like an activity or a fragment) and allows other objects to observe this state. Lifecycle uses two main enumerations to track the lifecycle status for its associated component. It means: Lifecycle it holds ...

What is ViewPager? ViewPager (android.support.v4.view.ViewPager) is a class in the Android extension package v4. This class allows users to switch the current view left and right to achieve the effect of sliding switch. Before using this class, you must understand: The ViewPager class directly inherits the ViewGroup class, that is ...

Blog Homepage 1. MVC architecture design and classic three-tier model MVC: model view controller, classic mode, easy to manage. Model: business layer and model layer, entity model and business related code View: view layer, which corresponds to layout layout file in android Controller: control layer, UI operation in android, corresponding to A ...

config/setting_user.php append content (all of the following, be careful not to use Chinese quotation marks, double quotation marks and semicolons) //[specify multiple languages and keep Chinese only] $GLOBALS['config']['settings']['language'] = 'zh-CN'; //[automatically create a new directory when creating a user-defined group] $GLOBALS['conf ...

HashMap is almost the knowledge that must be asked in an interview. Can you really take it easy for an interview with HashMap? I believe that if you go to an interview with a famous Internet company, you will never just ask such a simple question as the data structure of HashMap. I collected several questions that the boss often asked about Ha ...

03-HK integrated Redux This article is hkzf The series of mobile tutorials aims to help beginners quickly master the project development based on React technology stack through a series of articles. Redux introduce motivation JavaScript needs to manage more states than ever, and Redux tries to make state changes predictable Three principles S ...

It is not practical to use css to realize waterfall flow, because the waterfall flow realized in Chaoshan city is arranged in columns. Here, we record the realization of waterfall flow with js and the realization of waterfall flow with left and right columns in wechat applet 1. effect picture 2. Native js realizes waterfall flow html file < ...

20190214 questions What happened in new Vue()? First of all, from the perspective of syntax, the new keyword represents the instantiation of an object in js language, while Vue is actually a class. Let's take a look at the source code Source address https://github.com/vuejs/vue/... // From the source code, we can see that the vue class is very ...