投稿時間:2021-10-18 04:24:47 RSSフィード2021-10-18 04:00 分まとめ(26件)

カテゴリー等	サイト名等	記事タイトル・トレンドワード等	リンクURL	頻出ワード・要約等/検索ボリューム	登録日
python	Pythonタグが付けられた新着投稿 - Qiita	YOLOv5で特定の物体のみ検出し、写真をくり抜く方法	https://qiita.com/S-R-Programming/items/ba5e62b0da048c69addd	実行コマンドに「class番号」を追加します。	2021-10-18 03:17:15
js	JavaScriptタグが付けられた新着投稿 - Qiita	初心者JavaScriptのセミコロン『 ; 』	https://qiita.com/yan_satoru/items/290e3c298e2caa79e886	初心者JavaScriptのセミコロン『』『』いつ使うJavaScriptを勉強していると、文末のをどうしても忘れてしまう・・・。	2021-10-18 03:36:01
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	Canvasで生成したオブジェクトにブラー効果をかけることができますでしょうか？	https://teratail.com/questions/364916?rss=all		2021-10-18 03:21:25
Program	[全てのタグ]の新着質問一覧｜teratail（テラテイル）	pythonで堅牢に通信	https://teratail.com/questions/364915?rss=all	httpserver	2021-10-18 03:12:39
海外TECH	DEV Community	Why Good Syntax Highlighting is Important	https://dev.to/aboss123/why-good-syntax-highlighting-is-important-4gan	Why Good Syntax Highlighting is ImportantAll code snippets posted are under the MIT License So does it really matter Yes There good programming practices in certain programming languages but there is also good developing practices and this is one of them So what are the advantages Higher Productivity When programming with better syntax highlighting it becomes easier to identify where parts of your program is based on the color With color schemes with limiting syntax highlighting on certain semantics it can be really difficult to differentiate between what may be a parameter variable or a local variable or in the case of C macros enum values global variables etc Encourages you to codeWhat do I mean by this I mean that you actually feel more engaged looking at a diverse array of colors on your screen rather than dull jumbled array of words that happen to put together a program Let me show you what I mean Good Example Snippet from Jet What does this do well It has a vast amount of colors that is easy to differentiate parts of the program immediately it is not just about I have highlighting but it really tries and brings out different parts of the program I can easily point out macros class variables parameters and functions almost instantly through this highlighting There are benefits to this in dynamically typed languages too let s have a look at JavaScript Of course this also depends on your editor s capability but other popular editors like Visual Studio Code still provide support for semantic highlighting But we can see clearly how this highlighting improves the coder s experience and provides clarity Not so Great Example This theme is known as Dracula JetBrains s default dark theme syntax highlighting and while it does the job makes me feel less excited to code Important type values such as size t are not highlighted in this example and can easily be overlooked as they have a very similar color to the delimiter tokens Disadvantages of Good Syntax HighlightGet lost in the sea of colors that is your codeNo That s just me Well let s move on then ConclusionMy opinion is this the making of a good programmer is one that knows how to use the tools available today to further increase their skills and this includes something as subtle as syntax highlighting and font choice	2021-10-17 18:30:11
海外TECH	DEV Community	Pop culture design patterns: creational	https://dev.to/mestrak/pop-culture-design-patterns-creational-3m32	Pop culture design patterns creationalDuring a recent interview I asked the candidate about their understanding of design patterns I was impressed not only with their honesty telling me they only had basic knowledge but also with their description of the Singleton pattern It s like Highlander …there can be only one Since then I discovered that there are already some memes floating around with the same joke but it made me chuckle anyway It got me thinking that perhaps there is something in the idea of using pop culture references to remember the fundamental goals of design patterns This series is my attempt to choose some good references It s not to be taken too seriously and I won t provide in depth explanations of each pattern as there are already amazing sites for this like Let s try creational patterns first Here goes … Singleton Highlander there can be only oneImage sourced from Singleton ensures that only one instance of the class which implements it can exist Global access to that object can be used within state management applications think Redux If you haven t seen The Highlander you re missing out I love it even though it s s cheese Immortals battle it out to be the only immortal because just like the Singleton pattern THERE CAN BE ONLY ONE Other similarities between Singleton and The Highlander They re both classics and both much criticised I m not afraid to say that I love both of them I can still remember my first time implementing a Singleton In The Highlander after beheading another immortal all knowledge that person has obtained during their lifetime is transferred to the surviving immortal in a process called The Quickening One of the criticisms of Singleton is that it can be used as a global store for everything resulting in separate components of an application knowing too much about each other Builder Five GuysImage sourced from The goal of the Builder pattern is to construct complex objects and allow you to create variations on those objects using the same code A frequently used analogy for this pattern is assembling a meal in a fast food restaurant My somewhat limited imagination allowed me to think of Five Guys Think of making a burger as a complex task implement the Builder pattern to call AddPickles AddBacon AddCheese AddKetchup Obviously if those are your only choices of Five Guys burger toppings something has gone wrong but hopefully you get the idea Builder also has an optional implementation of a Director further abstracting the implementation and simplifying things for the client This is like your Five Guys cashier who takes your order for a burger all the way and a crazy milkshake with mixins and then sends all required instructions to the builder team who assemble and deliver your meal Prototype Futurama SE BenderamaImage sourced from The Prototype pattern is used to remove complexity from copying objects Objects that implement the Prototype pattern know how to clone themselves so code that needs to make a copy does not need to know the complexity of the class In Benderama Bender makes clones of himself Unfortunately each clone is smaller than the previous one and when they reach molecular level they nearly destroy the world Obviously knowing that detail this analogy falls down entirely Factory Method The Pepsi ChallengeImage sourced from Factory Method provides a way for a class to create similar objects but to leave the individual subclasses to use their own logic This is done by defining an interface implemented by all subclasses so individual objects can be created using common methods but without knowing the details of what s inside First of all in case you don t know what it is the Pepsi Challenge is a marketing campaign from the s where shoppers would do a blind tasting of Coke and Pepsi and say which one they preferred Why is Factory Method similar to the Pepsi Challenge Think of an abstract class called SoftDrink which provides a creational method CreateDrink And an interface implemented by every soft drink providing the following common methods FillBottle OpenBottle PourDrink DrinkCola This is Factory Method The creational logic of each drink is the secret recipe closely guarded by Coke or Pepsi When the consumer takes the challenge they call the DrinkCola function but they do not know if they are doing that for Coke or Pepsi thanks to the Factory Method which hides that complexity in the form of a big yellow box Using this approach Pepsi could add as many drinks as they want to into the challenge They don t really need to do that though as instead through shameless capitalism the two companies have successfully wiped out or bought out most other competition One drawback of the Factory Method is that requires implementation of many subclasses This can make quite a simple concept harder to understand than intended when actually implemented just like my attempt to use the Pepsi Challenge to explain this pattern Abstract Factory IkeaImage sourced from You may guess from the name that this one adds a layer of abstraction to the Factory Method It is used for creating groups of related objects a family The Abstract Factory class holds a bunch of abstract creation methods which know how to create instances of the objects Concrete factories will then be called to actually create the object Think of each family like a set of matching furniture from Ikea The furniture family might contain a chair sofa and a table Different style chairs would have the same chair interface the create method would implement the style of that chair s given family The factory for a given family will call the specific create methods to create each furniture type with the correct style matching the family I m sorry to say that I had a lack of imagination for this one and the chosen analogy is the same as several other examples online One of those is the excellently written article on which has a great explanation I recommend that you spend some time reading that and hopefully the Ikea link will start to stick And there you have it hopefully some memorable references for Singleton Builder Prototype Factory and Abstract Factory creational design patterns Look out for further posts in this series where I will try to do the same for Structural and Behavioural patterns Fin	2021-10-17 18:28:44
海外TECH	DEV Community	8 Steps Guide To Ace A System Design Interview	https://dev.to/sunilc_/8-steps-guide-to-ace-a-system-design-interview-2j8b	Steps Guide To Ace A System Design InterviewSystem Designing has become one of the important rounds to crack a Software Developer job interview especially for a senior level position Preparing for this round is necessary to crack interviews of some of the popular companies like Amazon Netflix Google Twitter etc In this round you are basically expected to discuss the design of a large scale distributed system like Twitter Uber Facebook Dropbox etc  There is no one right solution when it comes to designing a system There can be multiple ways to solve a problem and thus this round is going to be an open ended round where the focus will be on a working design your thought process Why Is It Important To Prepare for a System Design Round Due to the lack of experience or knowledge in building scalable systems in everyday work a lot of developers struggle with this round Even after being a good Software Developer they fail to get into good companies just because they fail to clear this round So it s important to focus on this round and prepare well to get into your dream company What To Expect in a System Design Interview Great engineers spend years of time building a robust and scalable system You cannot possibly come up with a similar solution in a short duration of hours in a System Design interview  So generally only a part of the entire system is discussed in this round As mentioned earlier there is no one right solution in designing a good system This round is generally open ended and discussion can go in any direction based on what the interviewer is interested in how you lead the discussion and in what direction you take it Sample Questions Asked in a System Design Interview Design a chat service like WhatsAppDesign a parking lotDesign a URL shortener service like TinyURLDesign a video streaming service like YouTube NetflixDesign a file sharing service like Google DriveDesign a Social Media platform like Instagram Twitter or Facebook These are some of the popular questions that are asked in this round As you can see the questions are vague and the problem statement doesn t provide specific details on what part of the system should be designed  So it s important to know how to approach this round to come up with a good design at the end of this discussion Different System Design Rounds System Design is generally split into two separate rounds  But again it depends on the company and its process So be prepared to design both high level and low level components of a system in this round High level DesignLow level Design High Level Design This round mainly checks your ability to architect amp design high level components for the given requirements For example given a problem statement like Design a social media platform like Instagram you need to come up with the different microservices you will need the pub sub mechanism if needed queues databases caching etc The interviewer will ask questions on how data would flow through different microservices in the design fault tolerance retry mechanism etc You can also expect questions around non functional requirements like scalability data consistency concurrency etc Building a distributed scalable system is hard You need to think about different scenarios while coming up with an architecture Different concepts you should learn about to prepare for an HLD round Key Characteristics of Distributed SystemsLoad BalancingCachingData PartitioningIndexesProxiesRedundancy and ReplicationSQL vs NoSQLCAP TheoremConsistent HashingLong Polling vs WebSockets vs Server Sent Events Low Level Design This round mainly focuses on your ability to design low level components of your HLD Given a problem statement you should come up with a design with different entities classes amp attributes inheritance composition design patterns databases tables amp schema etc You cannot possibly cover all of these in one interview round The interviewer may be interested in anyone depending on how the discussion goes Different concepts you should learn about to prepare for an LLD round UMLUse case diagramClass diagramDatabase designSequence diagramActivity diagramSeparation of concernsOOP principlesSOLID principles etc How To Approach a System Design Interview Round Here is my step guide to approaching System Design rounds effectively Step Ask a lot of questions and set the scope for the interview System Design problem statements are vague And there s no one right answer So it s important to ask a lot of questions and clarify the scope of the discussion Candidates who ask a lot of questions have a better chance of success For example here is a list of questions you can ask for the Design Instagram question What are the different types of accounts possible A Only users We will not consider business accounts for nowWhat type of posts can a user post A Let s consider users can post only images for this discussion Videos are out of scope Can users follow other users A YesShould we support tags for each post A YesCan posts be private A Let s assume posts can only be public for this discussion Can users search for posts A YesShould we focus on the client side architecture or the server side architecture A I would like to understand the client server interaction on a high level But the focus should be more on building a scalable backend system How many users are expected to use the system every day A Let s assume we have around M users logging in every day Should we focus on generating a user s home feed A Let s not focus on the feed generation algorithmShould we focus on the high level or low level design of the system A Let s discuss the high level design of the system in this discussionThese are some of the example questions you can ask to set the scope of the discussion As you see now we know we need to focus on building the high level design of Instagram We don t need to consider users posting videos We don t need to consider generating users home feeds in an intelligent way etc Step System Interface DefinitionOnce we have the requirements finalized the next step is to come up with a list of APIs we will need to build the system You should define the different REST APIs and their contract to support the requirements given For example in our Instagram example here are some example APIs we will need storePhoto user id tags image url user location … getPhoto image id likePhoto image id user id Of course these are example APIs The APIs used in a real world application are much more complicated Step Capacity Estimation and ConstraintsYour system should have enough storage and resources to handle the expected load and number of users who might use your system in year from now years from now etc So it s important to estimate how much resources you need to allocate when designing a system to avoid running into problems in the future If you have a database in your system design cache in your system the capacity estimation process generally involves calculating how much memory is used on a daily basis across all the databases and cache clusters  This gives us a good estimation of how much memory we will need in years from now Capacity estimation also helps in the way we design our system so that it is horizontally and vertically scalable for higher capacity requirements in the future Here s a calculation of how much storage is needed to store photos in our Instagram example We have M users log in every day based on our assumption aboveLet s assume M users upload an average of photos every dayM photos are uploaded every dayThis computes to photos added every secondLet s assume an average photo size of KBStorage needed each day M KB gt GBStorage needed for years GB days a year years TBStorage needed for years GB days a year years TB Step High Level DesignAt this point it helps to list down all the high level components that are involved in the system and how they interact with each other  It can be microservices databases caches messaging queues low cost storage services etc For our Instagram example we can create two separate microservices One service is responsible for uploading the photos Another service for retrieving the photos What s the point of two separate microservices you may ask The reason for this is the upload photos requests are generally lower than reading photos requests So we can scale the services separately based on the traffic demands We can even use low cost storage to store photos and a SQL metadata database to store the details about a photo like uploaded by location image name size created at etc You should be able to explain how the data would flow through these high level components once you have this ready Step Database Schema DesignIn DB design we decide what kind of database suits our use case A SQL or NoSQL and also the entities and the relationships between them If we re building a banking application where the movement of money is involved we cannot use NoSQL databases that are eventually consistent in nature Similarly we cannot use a SQL database where data changes very frequently In our Instagram example we can use a NoSQL database to store metadata details for a post Why Because a post may have properties like likes image url created at created by etc But in the future let s say we want to introduce other features like dislike tags etc it can be easily done using a NoSQL DB without any schema changes Step Class DesignIn class design we come up with the low level class entities which share the same responsibilities relationships operations attributes and semantics We basically list down the classes their attributes methods and their relationship with other classes The way you re evaluated depends on whether you re using the right object oriented concepts principles and design patterns A good system is designed keeping all of these in mind Abstraction Encapsulation Inheritance amp Polymorphism It s also important to learn about the SOLID principles The First Principles of Object Oriented Design These principles will help you design software that is easier to maintain and extend as it grows S   Single responsibility PrincipleO   Open closed PrincipleL   Liskov Substitution PrincipleI   Interface Segregation PrincipleD   Dependency Inversion Principle Step  CachingA cache is a high speed in memory data storage layer to store data for faster access in the future It s a means to improve the overall system performance Caching is important in any system that needs to scale  We basically cache the data that is frequently used Doing this will result in applications taking lesser time compared to accessing the data from a database every time In our Instagram example we can cache the metadata of photos like created by location created at etc since these parameters are never going to change for a given photo Other parameters like comments likes etc cannot be cached since they are changing frequently The moment we start using cache in our design we also need to think about the eviction policies Since caches are costlier than database storage we have to keep a check on the amount of data we store in a cache So cache eviction becomes important There are many eviction policies like LRU Least Recently Used FIFO First In First Out LFU Least Frequently Used etc Step Data Partitioning ShardingOften times it happens that all the data in our application cannot be stored on a single database server In cases like these we need to come up with strategies to store the data on multiple database servers Here we basically split the large set of data into multiple chunks logical partitions and we store these chunks on multiple nodes Sharding is a good technique to scale a growing application There are many techniques to partition data Range based partitioningHash based partitioningDirectory based partitioningVertical partitioning etcYou should read about these in order to understand which partitioning schemes are suitable in which scenarios This steps approach gives you a framework to approach any system design question But remember that the interviewer may be interested in any one of these steps in which case you should be able to focus only on that step and figure out the details More Tips System before scaleMany candidates try to focus on building a scalable system before even they have a design for a working system Focus on building the system first and then think about scaling it Start High level and then drill downStart with writing down the high level components we need for the system we are building Then drill down on any of the lower level components the interviewer suggests  This keeps your mind clear and helps you design a better system during the interview Mention all the assumptions you re makingYou should mention all the assumptions you re making during the interview It s important that you and the interviewer are on the same page Consider both function and non functional requirementsKeep both functional and non functional requirements in mind when designing the system Sometimes it becomes difficult to support non functional requirements like consistency availability data durability etc Core AlgorithmSome systems need a core algorithm to be implemented for the system to work For example if you want to designs a TinyURL like system you need to come up with an algorithm to generate the tiny URLs for a given long URL Not many system design questions need a complex algorithm to be implemented Design for the right scaleThe same system can be designed in completely different ways based on the scale needed So clarify the scale you re designing the system for at the beginning of the discussion Recommended Courses To Prepare For System Design Interviews Here are the best courses that I recommend for preparing for System Design interviews Grokking the System Design InterviewGrokking the Object Oriented Design InterviewTech Dummies Narendra LSystem Design by Gaurav SenLow Level Design The Code Mate Conclusion Think of the System Design interview as an open ended discussion with your colleague You cannot possibly come up with the best possible solution for a system in the given hours Clarify all the requirements and set the scope for the discussion Make sure you and the interviewer are on the same page throughout the discussion Learn how to estimate the data capacity required in the next years and design the system for the capacity expected Mention all the assumptions you are making during the interview Given a problem statement try to think of all the high level components services databases caches message queues etc first Then figure out the lower level details of the system It is important to learn how to design classes databases and APIs It s is important to learn Object Oriented and SOLID principles for low level design interviews The interviewer wants to know how you approach a given problem and the thought process behind it As long as you are able to justify why a component is designed in a certain way you re good Practice solving system design problems That s the only way to do well in this round The article was originally published on my blog You can find it here You can connect with me on twitter where I usually share my knowledge more frequently on topics like Software Development freelancing creating multiple passive income streams etc	2021-10-17 18:02:00
海外科学	NYT > Science	West Virginia Leads U.S. in Flood Risk, Adding to Manchin’s Climate Dilemma	https://www.nytimes.com/2021/10/17/climate/manchin-west-virginia-flooding.html	West Virginia Leads U S in Flood Risk Adding to Manchin s Climate DilemmaAs the senator blocks Democrats push to reduce warming new data shows his constituents are more exposed to worsening floods than anywhere else in the country	2021-10-17 18:05:30
海外科学	NYT > Science	Democrats Weigh Carbon Tax After Manchin Rejects Key Climate Provision	https://www.nytimes.com/2021/10/16/climate/democrats-carbon-tax-climate.html	Democrats Weigh Carbon Tax After Manchin Rejects Key Climate ProvisionFaced with the likely demise of a central pillar of President Biden s agenda the White House and outraged lawmakers are scrambling to find alternatives	2021-10-17 18:09:28
海外科学	NYT > Science	Key to Biden's Climate Agenda Like to Be Cut Because of Manchin	https://www.nytimes.com/2021/10/15/climate/biden-clean-energy-manchin.html	Key to Biden x s Climate Agenda Like to Be Cut Because of ManchinThe West Virginia Democrat told the White House he is firmly against a clean electricity program that is the muscle behind the president s plan to battle climate change	2021-10-17 18:16:01
海外科学	BBC News - Science & Environment	Earthshot Prize: William and Kate joined by stars for awards ceremony	https://www.bbc.co.uk/news/uk-58948339?at_medium=RSS&at_campaign=KARANGA	london	2021-10-17 18:20:15
ニュース	BBC News - Home	Show kindness and love, say family of killed MP	https://www.bbc.co.uk/news/uk-58949153?at_medium=RSS&at_campaign=KARANGA	amess	2021-10-17 18:34:25
ニュース	BBC News - Home	Earthshot Prize: William and Kate joined by stars for awards ceremony	https://www.bbc.co.uk/news/uk-58948339?at_medium=RSS&at_campaign=KARANGA	london	2021-10-17 18:20:15
ニュース	BBC News - Home	Scotland beat Bangladesh in T20 World Cup after Oman win	https://www.bbc.co.uk/sport/cricket/58945819?at_medium=RSS&at_campaign=KARANGA	Scotland beat Bangladesh in T World Cup after Oman winShakib Al Hasan becomes the leading wicket taker in Twenty internationals but Scotland successfully defend against Bangladesh in the T World Cup in Muscat Oman	2021-10-17 18:03:26
ニュース	BBC News - Home	Newcastle 2-3 Tottenham: New era at St James' Park begins with loss	https://www.bbc.co.uk/sport/football/58833954?at_medium=RSS&at_campaign=KARANGA	Newcastle Tottenham New era at St James x Park begins with lossNewcastle s first game since the club s Saudi Arabia backed takeover ends in a defeat by Tottenham which intensifies the pressure on manager Steve Bruce	2021-10-17 18:43:01
ニュース	BBC News - Home	NFL London: Jacksonville Jaguars beat Miami Dolphins 23-20 in thriller	https://www.bbc.co.uk/sport/american-football/58947267?at_medium=RSS&at_campaign=KARANGA	NFL London Jacksonville Jaguars beat Miami Dolphins in thrillerTrevor Lawrence celebrates the first win of what could be a glittering NFL career after the Jacksonville Jaguars beat the Miami Dolphins in a thrilling finish in London	2021-10-17 18:54:53
ビジネス	ダイヤモンド・オンライン - 新着記事	40歳以降の視力矯正手術、レーシックの次は「眼内コンタクトレンズ」に注目の理由 - ニュース3面鏡	https://diamond.jp/articles/-/283913		2021-10-18 03:50:00
ビジネス	ダイヤモンド・オンライン - 新着記事	「国産シイタケ」の多くは中国栽培、本当の栽培地を見分ける簡単な方法とは - ニュース3面鏡	https://diamond.jp/articles/-/281471	高価	2021-10-18 03:45:00
ビジネス	ダイヤモンド・オンライン - 新着記事	社会保障負担の増加で伸び悩む手取りの給与、分配政策にデジタル活用を - 数字は語る	https://diamond.jp/articles/-/284637	一部の人	2021-10-18 03:40:00
ビジネス	ダイヤモンド・オンライン - 新着記事	米労働者430万人、仕事に復帰しないのはなぜ - WSJ PickUp	https://diamond.jp/articles/-/284942	wsjpickup	2021-10-18 03:35:00
ビジネス	ダイヤモンド・オンライン - 新着記事	米大手銀の決算から読み解く経済状況 - WSJ PickUp	https://diamond.jp/articles/-/284943	wsjpickup	2021-10-18 03:30:00
ビジネス	ダイヤモンド・オンライン - 新着記事	欧州ガス高騰、インフレへの影響は - WSJ PickUp	https://diamond.jp/articles/-/284944	wsjpickup	2021-10-18 03:25:00
ビジネス	ダイヤモンド・オンライン - 新着記事	相手や自分を否定しない「口ぐせリセット」で、人生も仕事も好転する！ - 要約の達人　from flier	https://diamond.jp/articles/-/284882	相手や自分を否定しない「口ぐせリセット」で、人生も仕事も好転する要約の達人fromflier「無くて七癖」というけれど、口ぐせについても同じだろう。	2021-10-18 03:20:00
ビジネス	ダイヤモンド・オンライン - 新着記事	【お寺の掲示板91】自分の敵はどこにいる？ - 「お寺の掲示板」の深～いお言葉	https://diamond.jp/articles/-/284266	鼓舞	2021-10-18 03:15:00
ビジネス	ダイヤモンド・オンライン - 新着記事	【アスリートも実践！】ストレスや逆境に対処する力「レジリエンス」が高まるメンタリティとは？ - 脳疲労が消える最高の休息法	https://diamond.jp/articles/-/284148	精神科医	2021-10-18 03:10:00
ビジネス	ダイヤモンド・オンライン - 新着記事	ひろゆきが語る「自己肯定感が高い人の口グセ」ベスト1 - 1％の努力	https://diamond.jp/articles/-/283705	youtube	2021-10-18 03:05:00