With var you have a function scope, and only one shared binding for all of your loop iterations – i.e. the i in every setTimeout callback means the same variable that finally is equal to 6 after the loop iteration ends. With let you have a block scope and when used in the for loop … Read more
Inside a pattern matching switch statement using a case for an explicit type is asking if the value in question is of that specific type, or a derived type. It’s the exact equivalent of is switch (someString) { case string s: } if (someString is string) The value null does not have a type and … Read more
Refer: Appending to and copying slices In Go, arguments are passed by value. Typical append usage is: a = append(a, x) You need to write: func main(){ var array [10]int sliceA := array[0:5] // append(sliceA, 4) // discard sliceA = append(sliceA, 4) // keep fmt.Println(sliceA) } Output: [0 0 0 0 0 4]
dynamic is a type underlying all Dart objects. You shouldn’t need to explicitly use it in most cases. var is a keyword, meaning “I don’t care to notate what the type is here.” Dart will replace the var keyword with the initializer type, or leave it dynamic by default if there is no initializer. Use … Read more
I highly recommend “The Joy of Clojure” or “programming Clojure” for a real answer to this question, I can reproduce a short snip-it of the motivations for each: start by watching this video on the notion of Identity and/or studying here. Refs are for Coordinated Synchronous access to “Many Identities”. Atoms are for Uncoordinated synchronous … Read more
Option Infer must be on in order for this to function properly. If so, then omitting the type in VB.NET (Visual Basic 9) will implicitly type the variable. This is not the same as “Option Strict Off” in previous versions of VB.NET, as the variable is strongly-typed; it’s just done so implicitly (like the C# … Read more
It’s really just a coding style. The compiler generates the exact same for both variants. See also here for the performance question: Will using ‘var’ affect performance?
What ReSharper suggests is clearly overuse of the var keyword. You can use it where the type is obvious: var obj = new SomeObject(); If the type is not obvious, you should rather write it out: SomeObject obj = DB.SomeClass.GetObject(42);
There’s no extra Intermediate language (IL) code for the var keyword: the resulting IL should be identical for non-anonymous types. If the compiler can’t create that IL because it can’t figure out what type you intended to use, you’ll get a compiler error. The only trick is that var will infer an exact type where … Read more
There is none. Alas, you have to type out the full type name. Edit: 7 years after being posted, type inference for local variables (with var) was added in Java 10. Edit: 6 years after being posted, to collect some of the comments from below: The reason C# has the var keyword is because it’s … Read more