clearInterval() not working [duplicate]
setInterval returns an ID which you then use to clear the interval.
scope
What are the double colons (::) in R?
As you probably have looked up the help page by now usage of :: helps to access the exact function from that specific package. When you load dplyr you probably got a message as follows.. So, for instance, if you would like to use intersect function from dplyr or base package, you need to specify using the :: double colons. Usage will be … Read more
What is the meaning of the dollar sign “$” in R function()?
The $ allows you extract elements by name from a named list. For example You can find the names of a list using names() This is a basic extraction operator. You can view the corresponding help page by typing ?Extract in R.
Dynamic and static Scoping program differences
Static scoping means that x refers to the x declared innermost scope of declaration that has one. Since h is declared inside the global scope, the innermost x is the one in the global scope(it has no access to the xs in f and g, since it was not declared inside them), so the program prints 14 twice. Dynamic scoping means that x refers to the x declared in the most recent frame of the call-stack the … Read more
How can I access global variable inside class in Python
By declaring it global inside the function that accesses it: The Python documentation says this, about the global statement: The global statement is a declaration which holds for the entire current code block.
How do I pass the this context to a function?
Javascripts .call() and .apply() methods allow you to set the context for a function. Now you can call: Which would alert FOO. The other way around, passing obj_b would alert BAR!!. The difference between .call() and .apply() is that .call() takes a comma separated list if you’re passing arguments to your function and .apply() needs … Read more
Angular 2 – Using ‘this’ inside setTimeout
You need to use Arrow function ()=> ES6 feature to preserve this context within setTimeout.
class not declared in scope – even though .h was included
The common circular include problem occurs with:a.h b.h If some cpp includes “a.h” you might get away with it (if b.h didn’t really need a.h). But if that cpp instead includes b.h then b.h includes a.h BEFORE declaring things needed by a.h. Then a.h tries to include b.h but the include guard blocks that, so the compiler … Read more
Error: ‘else’ without ‘if’
Remove the semicolon at the end of this line: And please, please use curly brackets! Java is not like Python, where indenting the code creates a new block scope. Better to play it safe and always use curly brackets – at least until you get some more experience with the language and understand exactly when you can omit them.
Java, “Variable name” cannot be resolved to a variable
If you look at the scope of the variable ‘hoursWorked’ you will see that it is a member of the class (declared as private int) The two variables you are having trouble with are passed as parameters to the constructor. The error message is because ‘hours’ is out of scope in the setter.