Harleen Sahni
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Nov 4, 2021 · Its a bang-bang operator used to force early evaluation of part of an expression before it gets fully evaluated. So, its forcing to evaluate that part of the expression before the rest. With more input, I could provide a more detailed answer. answered Nov 4, 2021 at 17:51. Spartacus Rocha.
Nov 27, 2020 · (bang-bang) was what I needed to force eval of the content of the variable; however, I did not get the expected output in my new column. Only the !!as.name gave me the output I was expecting, and I do not fully understand why. Could someone explain why in this case using only !! isn't appropriate and what is happening in !!as.name?
Objects are true, but the undefined value and null are both false. The double negation operator !! calculates the truth value of a value. It's actually two operators, where !!x means !(!x), and behaves as follows: If x is a false value, !x is true, and !!x is false. If x is a true value, !x is false, and !!x is true.
Feb 16, 2017 · AFAIK came from the C# land. With nullable types, C# got its bang too (pun, of course, intended). Yup, the Sir Tony's invention wroke a serious havoc on the world of procedural programming, and we still cleaning the fallout. Being the sweetest person, he still apologizes for it.
Nov 18, 2020 · I don't think you want to force the evaluation of first and last.You just want the names to construct the string "{lastName}, {firstName}".
The bang bang (!!) command is a shortcut to repeat the previous command you entered in your terminal. This command is very useful when you forget that you need admin rights to make a certain action, and lets you repeat it with super-user rights just by typing. sudo !! instead of typing arrow-up, scrolling to the beginning of the line, adding ...
Jan 20, 2018 · Kotlin's double-bang operator is an excellent sample for fans of NullPointerException (NPE). The not-null assertion operator !! converts any value to a non-null type and throws an exception if the value is null. val nonNull = str!!.length. If you write str!!, it'll return a non-null value of str (str is a String? here) or throw an NPE if str is ...
Apr 29, 2011 · Out of curiosity, I noticed that no bang and bang perform the fastest but somewhere in the evolution of Chrome at least, bang became faster than no bang. (Probably statistically insignificant but...) Is there a reason why? I don't know much about code beneath the hood but find it quite fascinating. –
This may be an example of the double-bang trick (see The Safe Bool Idiom for more details). Here I summarize the first page of the article. In C++ there are a number of ways to provide Boolean tests for classes. An obvious way is the operator bool conversion operator.
So what does this do? If the operand is 0, the inner ! converts it to 1, then the outer ! converts that to 0. If the operand is non-zero, the inner ! converts it to 0, then the outer ! converts that to 1. So !! converts a value to its boolean equivalent. If the value is 0, it remains 0, otherwise it becomes 1.
