大约有 45,000 项符合查询结果（耗时：0.0415秒） [XML]
Insert picture/table in R Markdown [closed]
...
Several sites provide reasonable cheat sheets or HOWTOs for tables and images. Top on my list are:
Pandoc readme, specifically tables
RStudio's RMarkdown, more details in basics (including tables) and a rewrite of pandoc's markdown....
What is a semaphore?
...equently used to solve multi-threading problems. My question to the community:
14 Answers
...
ASP.NET Web API OperationCanceledException when browser cancels the request
When a user loads a page, it makes one or more ajax requests, which hit ASP.NET Web API 2 controllers. If the user navigates to another page, before these ajax requests complete, the requests are canceled by the browser. Our ELMAH HttpModule then logs two errors for each canceled request:
...
Rotated elements in CSS that affect their parent's height correctly
...ble, even for non-text elements - but like many interesting things in CSS, it requires a little cunning. My solution also technically invokes undefined behaviour according to the CSS 2 spec - so while I've tested and confirmed that it works in Chrome, Firefox, Safari, and Edge, I can't promise you t...
What is the difference between localStorage, sessionStorage, session and cookies?
...road scope question, and a lot of the pros/cons will be contextual to the situation.
In all cases, these storage mechanisms will be specific to an individual browser on an individual computer/device. Any requirement to store data on an ongoing basis across sessions will need to involve your applica...
What is the !! (not not) operator in JavaScript?
...
Converts Object to boolean. If it was falsey (e.g. 0, null, undefined, etc.), it will be false, otherwise, true.
!oObject // inverted boolean
!!oObject // non inverted boolean so true boolean representation
So !! is not an operator, it's just the ! ope...
serve current directory from command line
...meone give me a hint, howto serve the current directory from command line with ruby? it would be great, if i can have some system wide configuration (e.g. mime-types) and simply launch it from every directory.
...
Does “display:none” prevent an image from loading?
Every responsive website development tutorial recommends using the display:none CSS property to hide content from loading on mobile browsers so the website loads faster. Is it true? Does display:none not load the images or does it still load the content on mobile browser? Is there any way to pre...
Visual Studio 64 bit?
Is there any 64 bit Visual Studio at all? Why not?
5 Answers
5
...
Add a default value to a column through a migration
...
Here's how you should do it:
change_column :users, :admin, :boolean, :default => false
But some databases, like PostgreSQL, will not update the field for rows previously created, so make sure you update the field manaully on the migration too.
...