error-handling

Error: could not find function … in R

There are a few things you should check : Did you write the name of your function correctly? Names are case sensitive. Did you install the package that contains the function? install.packages(“thePackage”) (this only needs to be done once) Did you attach that package to the workspace ? require(thePackage) (and check its return value) or … Read more

What does “Fatal error: Unexpectedly found nil while unwrapping an Optional value” mean?

Background: What’s an Optional? In Swift, Optional<Wrapped> is an option type: it can contain any value from the original (“Wrapped”) type, or no value at all (the special value nil). An optional value must be unwrapped before it can be used. Optional is a generic type, which means that Optional<Int> and Optional<String> are distinct types … Read more

Error:(45, 36) error: cannot find symbol method findViewbyId(int)

you are overriding findViewById, remove these lines from code on first screen/Java code (always paste code and stacktrace as text!) public void findViewById(int z1){ } as you see findViewById is always void… this method belongs to Activity and you shouldn’t mess with them. it work like a charm and will return you proper View. doc … Read more

warning C4018: '<' : signed/unsigned mismatch [closed]

The compiler is saying that comparing an unsigned variable against a signed variable is –not allowed considered bad practice. This is because of two’s complement representation of a signed variable. (unsigned short) 0xFFFF is 65535, and (short) 0xFFFF is -1. They both have same the in-memory representation but mean totally opposite things. So the compiler … Read more