Control Structures In R Programming - Practice Test

(A) Multi-line expressions with curly braces are just not that easy to sort through when working on the command line

(B) lappy() loops over a list, iterating over each element in that list

(C) lapply() does not always returns a list

(D) You cannot use lapply() to evaluate a function multiple times each with a different argument

(E) Dynamic scoping turns out to be particularly useful for simplifying statistical computations

(F) Lexical scoping turns out to be particularly useful for simplifying statistical computations

(G) The scoping rules of a language determine how values are assigned to free variables

(H) An environment is a collection of (symbol, value) pairs, i.e. x is a symbol and 3.14 might be its value

(I) The primary task of debugging any R code is correctly diagnosing what the problem is

(J) R provides only two tools to help you with debugging your code

(K) print statement can be used for debugging purpose

(L) The traceback() function must be called immediately after an error occurs

(M) Functions in R are "second class objects"

(N) The writing of a function allows a developer to create an interface to the code, that is explicitly specified with a set of parameters

(O) Functions provides an abstraction of the code to potential users

(P) Writing functions is a core activity of an R programmer

(Q) The sapply() function behaves similarly to lapply()

(R) With multiple factors and many levels, creating an interaction can result in many levels that are empty

(S) apply() can be thought of as a combination of split() and sapply() for vectors only

(T) You can use tsplit() to evaluate a function single time each with a same argument

(U) for will execute a loop a fixed number of times

(V) break will execute a loop while a condition is true

(W) if and else tests a condition and acting on it

(X) break is used to break the execution of a loop

(Y) A formal argument can be a symbol, a statement of the form 'symbol = expression', or the special formal argument

(Z) The first component of the function declaration is the keyword function

([) The value returned by the call to function is not a function

(\) Functions are also often written when code must be shared with others or the public

(]) The order of the packages on the search list does not matter

(^) R has separate namespaces for functions and non-functions

(_) Users can configure which packages get loaded on startup so if you are writing a function

(`) The search list can be found by using the search() function

(a) Statements cannot be grouped together using braces '{' and '}'

(b) Computation in R consists of sequentially evaluating statements

(c) Single statements are evaluated when a new line is typed at the end of the syntactically complete statement

(d) next is used to skip an iteration of a loop

Control Structures In R Programming - Study Mode

[#1] The only environment without a parent is the . . . . . . . . environment.

Correct Answer

[#2] The . . . . . . . . function is a kind of "constructor function" that can be used to construct other functions.

Correct Answer

[#3] Which function in R language is used to find out whether the means of 2 groups are equal to each other or not?

Correct Answer

[#4] What will be the output of the following R code? > f <- function() {
+ ## This is an empty function
+ }
> class(f)

Correct Answer

[#5] Point out the wrong statement?

Correct Answer

Control Structures In R Programming - Study Mode

[#1] The only environment without a parent is the . . . . . . . . environment.

Correct Answer

[#2] The . . . . . . . . function is a kind of "constructor function" that can be used to construct other functions.

Correct Answer

[#3] Which function in R language is used to find out whether the means of 2 groups are equal to each other or not?

Correct Answer

[#4] What will be the output of the following R code? > f <- function() { + ## This is an empty function + } > class(f)

Correct Answer

[#5] Point out the wrong statement?

Correct Answer

[#4] What will be the output of the following R code? > f <- function() {
+ ## This is an empty function
+ }
> class(f)