• Flex layout tutorial, front-end will be the basic skills, interview will be the foundation


    preface Flex is a common CSS3 layout, which can efficiently realize various page layouts with a small amount of code. It is a basic but necessary basic skill, which is often used in interviews. For example, the most basic let you realize the horizontal / vertical center of the elements, or extend it to other […]

  • Flex layout is learning and using


    preface Flex is the abbreviation for flexible box, meaning “flexible layout”, which is used to provide maximum flexibility for the box model. It provides powerful spatial distribution and alignment between the child elements of flexbox. Flex layout is the preferred solution for today’s layout. This article will introduce the basic properties of flexbox and feel […]

  • How to cross compile through xmake


    Xmake provides convenient and flexible cross compilation support. In most cases, there is no need to configure complicated toolchains prefix, for example:arm-linux-What As long as the toolchains directory satisfies the following structure (most cross tool chains are of this structure) /home/toolchains_sdkdir – bin – arm-linux-gcc – arm-linux-ld – … – lib – libxxx.a – include […]

  • A simple cross Report


    if object_id(N’test’, N’U’) is not null drop table test go with PivotTable as ( Select ‘xxx’ as CZY, ‘like’ as czlx, 2 as num union all Select ‘xxx’, browse ‘as czlx, 14 as num union all Select ‘YYY’, ‘Browse’ as czlx, 10 as num union all Select ‘zzz’, ‘Browse’, 30 union all Select ‘zzz’, ‘like’, […]

  • R language to realize fitting neural network prediction and result visualization


    Original link: http://tecdat.cn/?p=6691 Neural network has always been one of the fascinating machine learning models, not only because of the fancy back-propagation algorithm, but also because of their complexity (considering the deep learning of many hidden layers) and the structure inspired by the brain. Neural networks are not always popular, partly because they still have […]

  • Compared with SVM, how does FM model learn cross features? How to optimize it?


    In the calculation of advertising and recommendation system, CTR prediction is a very important link. To judge whether an item is recommended or not, it needs to be determined according to the ranking of CTR estimated click rate. The commonly used methods in the industry are artificial features + LR, gbdt + LR, FM and […]

  • Mysql database multi table query


    catalog Mysql database multi table query multi-table query Subquery Joint query Cross connect Internal connection External connection Left outer Right outer link Complete external connection Three table query Self connect Mysql database multi table query multi-table query Query results come from multiple tables, that is, multi table query Subquery: a query nested in an SQL […]

  • Cross compile GDB toolchain


    1. Cross compilation Cross compilation refers to the compilation of programs running on one platform. The platform here involves hardware and software. Hardware platform refers to CPU architecture and software platform refers to operating system. Cross compilation is mainly aimed at the embedded field. Because the resources of embedded system are limited, there is no […]

  • Understanding AI training set, verification set and test set (attachment: segmentation method + cross validation)


    Data is very important in AI technology! This article will introduce three kinds of data sets in detail: training set, verification set and test set. At the same time, it also introduces how to divide the data into three kinds of data sets more reasonably. Finally, I will introduce a way to make full use […]

  • Intersectionobserver scrolling


    IntersectionObserver Definition It is to listen for the root element and the target element to trigger a callback at the specified cross proportion Compatibility Compatible with part of the modern browser (chrome) production environment, please pay attention to the compatibility requirements Usage scenarios Onscroll can be replaced in certain scenarios1. More simple and elegant writing2. […]

  • Flex web page layout CSS flexible expansion box syntax tutorial


    Layout is a key application of CSS. The traditional solution of layout is based on box model, which depends on display attribute + position attribute + float attribute. It is very inconvenient for special layout, for example, vertical center is not easy to achieve. In 2009, W3C put forward a new scheme, flex layout, which […]

  • Maximum rectangle


    Use documents of Exec export default (arr) => { let result = [] let reg = /1{2,}/g //Express the two-dimensional array again and extract the adjacent 1 arr = arr.map(item => { let str = item.join(”) let r = reg.exec(str) let rs = [] while (r) { rs.push([r.index, r.index + r[0].length – 1]) r = […]