投稿時間:2023-02-06 07:10:17 RSSフィード2023-02-06 07:00 分まとめ(11件)

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IT	ビジネス+IT 最新ニュース	マイクロセグメンテーションとは何かを解説　ゼロトラスト・SASEに必須の技術、その役割とは	https://www.sbbit.jp/article/cont1/106057?ref=rss		2023-02-06 06:10:00
Google	カグア！Google Analytics 活用塾:事例や使い方	電子書籍時代だからこそ紙で読むべきマーケターにおすすめのビジネス書3選	https://www.kagua.biz/review/recomen3/20230206a0.html	電子書籍	2023-02-05 21:00:54
海外TECH	DEV Community	Checking if a value is a number in Javascript with isNaN()	https://dev.to/smpnjn/checking-if-a-value-is-a-number-in-javascript-with-isnan-h8c	Checking if a value is a number in Javascript with isNaN In Javascript we have numerous ways to check if something is or is not a number This is a particularly common task in Javascript where there is dynamic typing resulting in some unexpected things being classified as numbers Typescript fixes some of these issues but in this guide we ll cover how to check if something is a number in Javascript and the pitfalls you should avoid when trying to do that Introducing isNaNNaN is a special value in Javascript which stands for Not a Number If you try to parse a text string in Javascript as an int you ll get NaN let x parseInt hello Returns NaNNaN in itself is kind of confusing and you don t always get results you would expect NaN for example does not equal any other value including itself Testing this out will always return false NaN falseNaN NaN false foo NaN falseYou might think this all makes sense until you try to run typeof NaN which returns number So it turns out that NaN is of type number in Javascript after all typeof NaN number Ignoring these peculiariies Javascript comes with a built in function to test if something is not a number known as isNaN This function can easily be used to determine if a something would evaluate to NaN if it was run through something like parseFloat isNaN hello trueisNaN falseisNaN trueisNaN gt trueSince isNaN checks if something is not a number we can use isNaN to test if something is a number For example isNaN is an easy way to test if is a number isNaN isNaN makes sense in most cases but since it parses numbers it can cause some unexpected side effects For example Number n on BigInt types throws an error and therefore throws an error on isNaN too isNaN n trueTo resolve some of these problems Javascript just made a new method called Number isNaN It s mostly the same only it won t coerce the type to a number Number isNaN vs isNaNThey are commonly thought to be the same but isNaN and Number isNaN work differently isNaN essentially parses the input and tries to make a number out of it That s why you see problems when you try to do isNaN n since Number n throws an error Instead you can use Number isNaN The difference between isNaN and Number isNaN is that Number isNaN does not try to coerce the input into a number Unlike isNaN it simply takes the input and confirms if it is equal to NaN or not That makes So all of the following will return false since none of them are exactly equal to NaN Number isNaN falseNumber isNaN hello falseNumber isNaN gt falseNumber isNaN falsewhile the following will return true since they do return NaN Number isNaN trueNumber isNaN parseFloat hello trueEither Number isNaN or isNaN will solve most of your number checking needs but there is one additional way to check if something is a number in Javascript Using isInteger and isSafeInteger to check a number in JavascriptAs well as isNaN and Number isNaN the global methods isInteger and isSafeInteger can help you determine if something is simply an integer with no decimal points Just like Number isNaN both of these methods do not try to evaluate the contents as a number That means passing in a string will always return false while a normal integer will pass the test isInteger falseisInteger trueisSafeInteger falseisSafeInteger trueisSafeInteger differs from isInteger by checking that the number falls outside the bigint range i e within and so for most use cases isInteger will do the job Using typeof to check if something is a number in JavascriptThe final way to check if something is a number is to use typeof again this may fit your needs better for some cases since typeof Math sqrt returns number rather than NaN however things like n will still show a type of bigint typeof Math sqrt number typeof parseFloat number typeof number typeof n bigint However be careful since it is quite unreliable Since typeof NaN returns number you can run into some unexpected situations which you will generally want to avoid As such Number isNaN remains probably the best way to check if something is or isn t a number Here are a few unexpected typeof situations you ll generally want to avoid typeof parseFloat hello number since NaN is a numbertypeof NaN since this evaluates typeof and then divides by typeof number since this evaluates as NaN which is a numbertypeof NaN number since NaN is of type numbertypeof string ConclusionChecking if something is or is not a number in Javascript has some complexities but it s generally straight forward The key points are isNaN is commonly used but will evaluate its input as a number which may cause some inputs are incorrectly judged to be NaN or throw an error Number isNaN is a robust version of isNaN which checks if something is exactly equal to NaN It does not evaluate its contents as a numbertypeof can tell you if something is a number or not but it may lead to some unexpected situations since NaN is also of type number I hope you ve enjoyed this guide on checking if something is a number in Javascript You can also check out more of my Javascript content here	2023-02-05 21:51:17
Apple	AppleInsider - Frontpage News	Users discover iCloud Backup issues following iOS 16.3 update	https://appleinsider.com/articles/23/02/05/users-discover-icloud-backup-issues-following-ios-163-update?utm_medium=rss	Users discover iCloud Backup issues following iOS updateA number of users of iCloud are having trouble synching with iCloud Drive Photos and uploading their backups after updating to iOS a problem that seems linked to two factor authentication iCloud logoIn posts to Apple s support forums and to Reddit as well as for one reader who contacted AppleInsider it seems there is an issue for some users trying to interact with iCloud The instances follow the update to iOS which made security changes to enable physical security keys to be used to secure accounts as well as expanding Advanced Data Protection outside of the U S Read more	2023-02-05 21:42:56
海外TECH	Engadget	Amazon’s 2022 Kindle drops to a record low of $75	https://www.engadget.com/amazons-2022-kindle-drops-to-a-record-low-of-75-211908974.html?src=rss	Amazon s Kindle drops to a record low of If one of your goals for is to read more a new Kindle might inspire you to stick to that intention Amazon has discounted its entry level e reader Right now you can get the ad supported model in either Black or Denim for or off its usual price The percent discount marks a new all time low for the Kindle making this a great time to buy the e reader Amazon has also discounted the ads free model by Instead of it s at the moment The Paperwhite is on sale too It will set you back Engadget hasn t had a chance to review the new entry level Kindle That said judging from all the upgrades Amazon decided to incorporate into the device it s well worth the upgrade if you own an older e reader The new Kindle features a ppi e ink screen making its display as dense as the one on the more expensive Kindle Paperwhite Amazon also doubled the amount of storage to GB added USB C charging and made the Kindle s frame lighter Oh and the new model also features up to six weeks of battery life another upgrade over its predecessor Unless you re specifically looking for an e reader with a larger display most people are better off buying the entry level Kindle over its more expensive siblings Follow EngadgetDeals on Twitter and subscribe to the Engadget Deals newsletter for the latest tech deals and buying advice	2023-02-05 21:19:08
ニュース	BBC News - Home	New images show Nicola Bulley on day she disappeared	https://www.bbc.co.uk/news/uk-england-lancashire-64530529?at_medium=RSS&at_campaign=KARANGA	bulley	2023-02-05 21:35:44
ニュース	BBC News - Home	Harry Kane: Tottenham striker overtakes Jimmy Greaves as Spurs' all-time top scorer	https://www.bbc.co.uk/sport/football/64532175?at_medium=RSS&at_campaign=KARANGA	Harry Kane Tottenham striker overtakes Jimmy Greaves as Spurs x all time top scorerHarry Kane moves ahead of Jimmy Greaves to become Tottenham s all time top goalscorer with his th goal for the club	2023-02-05 21:30:19
ニュース	BBC News - Home	Tottenham Hotspur 1-0 Manchester City: Harry Kane passes Jimmy Greaves as Spurs' all-time top scorer	https://www.bbc.co.uk/sport/football/64442953?at_medium=RSS&at_campaign=KARANGA	Tottenham Hotspur Manchester City Harry Kane passes Jimmy Greaves as Spurs x all time top scorerHarry Kane becomes Tottenham s all time record scorer surpassing the great Jimmy Greaves as his th goal for the club dents Manchester City s title ambitions at a raucous Tottenham Hotspur Stadium	2023-02-05 21:12:35
ニュース	BBC News - Home	West Ham United 0-0 Arsenal: Gunners falter in WSL title race	https://www.bbc.co.uk/sport/football/64442925?at_medium=RSS&at_campaign=KARANGA	West Ham United Arsenal Gunners falter in WSL title raceArsenal dropped points for the second successive Women s Super League match after being held to a goalless draw by West Ham United on Sunday evening	2023-02-05 21:40:05
ニュース	BBC News - Home	Garth Crooks' Team of the Week: Kane, Rashford, Mitoma, Dawson, Tarkowski, Tete, Onana	https://www.bbc.co.uk/sport/football/64526671?at_medium=RSS&at_campaign=KARANGA	Garth Crooks x Team of the Week Kane Rashford Mitoma Dawson Tarkowski Tete OnanaWho has been turbocharged by a new manager and whose stunning display got Leicester back on track It s Garth Crooks Team of the Week	2023-02-05 21:44:57
ビジネス	東洋経済オンライン	三菱｢デリカミニ｣5月発売､ブランド復権の狼煙 ついに全貌が明らかに､すでに先行受注も開始 | 新車レポート | 東洋経済オンライン	https://toyokeizai.net/articles/-/649348?utm_source=rss&utm_medium=http&utm_campaign=link_back	三菱自動車	2023-02-06 06:40:00