Imagine you need to create a recursive function in R that computes the nth Fibonacci number. How would you do this?
- fibonacci <- function(n) { if (n <= 1) { return(n) } else { return(fibonacci(n - 1) + fibonacci(n - 2)) } }
- fibonacci <- function(n) { if (n <= 1) { return(0) } else { return(fibonacci(n) + fibonacci(n - 1)) } }
- fibonacci <- function(n) { if (n <= 1) { return(1) } else { return(fibonacci(n + 1) + fibonacci(n - 1)) } }
- All of the above
To create a recursive function in R that computes the nth Fibonacci number, you can use the following code: fibonacci <- function(n) { if (n <= 1) { return(n) } else { return(fibonacci(n - 1) + fibonacci(n - 2)) } }. The function checks if the input n is less than or equal to 1. If it is, it returns n (base case). Otherwise, it recursively calls itself to calculate the Fibonacci number by summing the two previous Fibonacci numbers.
Suppose you're asked to write a function in R that takes an array of numbers and returns a new array with each element squared. How would you do it?
- Use a nested for loop to iterate over each element and calculate the square
- Use the apply() function with a custom function to calculate the square of each element
- Use the ^ operator to raise the array to the power of 2
- Use the sqrt() function to calculate the square root of each element
To write a function in R that takes an array of numbers and returns a new array with each element squared, you can use a nested for loop to iterate over each element of the array and calculate the square. By storing the squared values in a new array, you can return the resulting array as the output of the function.
Suppose you're asked to write a for loop in R that prints the squares of the numbers 1 to 10. How would you do it?
- for (i in 1:10) { print(i^2) }
- for (i in 1:10) { print(i * i) }
- for (i in 1:10) { print(square(i)) }
- for (i in 1:10) { print(pow(i, 2)) }
To print the squares of the numbers 1 to 10, you can use the for loop for (i in 1:10) { print(i^2) }. It iterates through the values 1 to 10, calculates the square of each value, and prints the result.
How would you handle missing values when calculating the median in R?
- Use the na.rm = TRUE parameter in the median() function
- Replace missing values with the median of the remaining values
- Exclude missing values from the vector before using the median() function
- All of the above
When calculating the median in R, you can handle missing values by using the na.rm = TRUE parameter in the median() function. Setting na.rm = TRUE instructs R to ignore missing values and compute the median based on the available non-missing values. This ensures that missing values do not impact the calculation.
What are some potential issues with using while loops in R and how can they be mitigated?
- Infinite loops, where the condition never becomes false
- Performance issues with large data sets
- Code complexity and readability concerns
- All of the above
One potential issue with using while loops in R is the risk of creating infinite loops, where the condition never becomes false. This can lead to the program running indefinitely. To mitigate this, it is important to ensure that the condition in the while loop eventually becomes false based on the desired logic. Additionally, it is crucial to monitor the loop's execution and include appropriate break conditions to exit the loop when necessary.
The ______ function in R can be used to calculate the geometric mean.
- mean()
- median()
- sum()
- expmean()
The mean() function in R can be used to calculate the geometric mean by taking the mean of logarithmic values. By applying the logarithm to the values, taking their mean, and exponentiating the result, you can obtain the geometric mean.
You're asked to print a sequence of numbers from 1 to 10 in R. How would you do it?
- None of the above
- print(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
- print(1:10)
- print([1,10])
In R, the colon operator ':' generates a sequence of numbers. So, to print a sequence of numbers from 1 to 10, the syntax would be print(1:10).
The ______ parameter in the scatter plot function in R can be used to change the size of the points.
- col
- pch
- cex
- marker
The cex parameter in the scatter plot function in R can be used to change the size of the points. It allows you to specify a numerical value that determines the relative size of the points on the scatter plot.
To calculate the median of a numeric vector in R, you would use the ______ function.
- median()
- mean()
- sd()
- var()
To calculate the median of a numeric vector in R, you would use the median() function. The median() function returns the middle value of a sorted vector or the average of the two middle values if the vector has an even number of values.
How do you determine the length of a string in R?
- len()
- length()
- nchar()
- strlen()
In R, the nchar() function is used to determine the length of a string. For example, nchar("Hello") would return 5.