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How to get first character of string?

...le what you say is true, unfortunately charAt() without any parameters actually runs about 10x slower than chartAt(0) in Firefox as of Firefox 71. See for yourself here: jsperf.com/testing-the-first-character-in-a-string/1 – Stephen M Irving Dec 16 '19 at 21:54...
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What are the precise rules for when you can omit parenthesis, dots, braces, = (functions), etc.?

...can omit dot when using the prefix, infix and postfix notations -- the so called operator notation. While using the operator notation, and only then, you can omit the parenthesis if there is less than two parameters passed to the method. Now, the operator notation is a notation for method-call, whi...
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What is the point of the diamond operator () in Java 7?

The diamond operator in java 7 allows code like the following: 7 Answers 7 ...
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How to organize large R programs?

...l as a means for namespaces. Just running source() over code works for really short snippets. Everything else should be in a package -- even if you do not plan to publish it as you can write internal packages for internal repositories. As for the 'how to edit' part, the R Internals manual has ex...
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Where in memory are my variables stored in C?

...declared in functions), variables (in main function), pointers, and dynamically allocated space (using malloc and calloc) get stored in memory? ...
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Formatting floats without trailing zeros

...ptimization is bad, but it's because the OP's trick requires you to remove all zeroes THEN all decimals and then NOT MORE ZEROS. Gabriel's approach just removes all zeros and periods until it hits something else. – Scott Stafford May 11 at 14:47 ...
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When should TaskCompletionSource be used?

AFAIK, all it knows is that at some point, its SetResult or SetException method is being called to complete the Task<T> exposed through its Task property. ...
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How do I set up DNS for an apex domain (no www) pointing to a Heroku app?

... (Note: root, base, apex domains are all the same thing. Using interchangeably for google-foo.) Traditionally, to point your apex domain you'd use an A record pointing to your server's IP. This solution doesn't scale and isn't viable for a cloud platform like H...
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SELECT * FROM X WHERE id IN (…) with Dapper ORM

... Directly from the GitHub project homepage: Dapper allow you to pass in IEnumerable and will automatically parameterize your query. connection.Query<int>( @"select * from (select 1 as Id union all select 2 union all select 3) as X where Id in @Ids", ...
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What does @@variable mean in Ruby?

...the classes; setting the value in an instance of one changes the value for all other instances of that class and even child classes, where a variable named @shared, with one @, would not be. [Update] As Phrogz mentions in the comments, it's a common idiom in Ruby to track class-level data with an ...