Tag：Examples
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Time：2021-5-9
(after editing this article, I found that the content of this article should belong to the advanced level of angularjs. There are a few examples of laziness, using the official demo and adding some comments. I’m sorry.). The previous article introduced various commonly used angularjs built-in directives and corresponding code examples. In this article, let’s […]
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Time：2021-5-8
1、 Reference Introduction to regular expressions 2、 Foundation 2.1 quantifier metacharacter expression explain Examples * >= 0 + >1 ? <=1 {m} =m {m,} >=m {m,n} >=m <=n
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Time：2021-5-7
Sometimes, we don’t want two adjacent columns to be close to each other, but we don’t want to use margin or other technical means. At this time, you can use the column offset function to achieve. Using column offset is also very simple. Just add the class name “col MD offset – *” to the […]
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Time：2021-5-7
stayPrinciple and practice of spark connector readerIn, we mentioned that spark connector is a data connector of spark, which can be used to read and write external data system. Spark connector includes two parts: reader and writer. This paper mainly describes how to use spark connector to write Nebula graph data. Spark connector writer principle […]
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Time：2021-5-6
Time, no matter in any life situation, is a very important concept. Just imagine, if there is no time, almost everything in this world will be in disorder, but at the same time, many scientists will also ask, in the objective world, does time really exist（ It’s a bit far away Back to the point, […]
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Time：2021-5-5
Why is channel concurrent and secure? The reason is that mutex is used in channel to ensure the security of concurrency.In go language, there are not only easy-to-use and advanced synchronization mechanisms such as channel, but also primitive synchronization mechanisms such as sync.mutex and sync.waitgroup. Through them, we can control the synchronization of data and […]
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Time：2021-5-5
Example 29 Latin square Problem description A Latin square matrix of order NxN is constructed so that the numbers 1 to N in each row and column of the square matrix appear only once. If n = 4: 1 2 3 4 2 3 4 1 3 4 1 2 4 1 2 3 […]
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Time：2021-5-5
Link to the original text:http://tecdat.cn/?p=21825 = The basic principle of hypothesis testing is the principle of small probability, that is, we think that small probability events can not happen in a test. = The problem of multiple comparisons When multiple hypothesis tests are carried out under the same research problem, it is no longer in […]
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Time：2021-5-4
Example 30 Censoring problem Problem description Enter a high-precision positive integer num (Num no more than 250 bits) from the keyboard. After removing s digits, the remaining digits will form a new positive integer according to the original order. Write a program, for a given num and s, to find a solution, so that […]
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Time：2021-5-4
Initial use of MySQL MySQL example library navicat15 Query MySQL version Mysql shell > select version(); Right bracket, notversion View initial password “Super administrator account” will be created when MySQL is launched for the first [email protected], the initial password is stored in the log file, through grep search and view: grep ‘temporary password’ […]
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Time：2021-5-4
In database query, join is one of the most commonly used queries. Due to the complexity of join algorithm implementation, the probability of problems is high. We analyze the join problems in tidb and classify the problem prone scenarios into the following categories: For the same join query, the join key is of different data […]
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Time：2021-5-4
NLogNLog is a flexible and free logging platform for various. Net platforms (including. Net standard). NLog can write logs to multiple targets, such as database, file, console and mail. Here’s how to use NLog. Use steps Add reference Install NLog nuget package:Install-Package NLog.Config; Add profile Add a configuration file to the project (you can also […]
