The ______ function in R can be used to explode segments in a pie chart.
- explode()
- pull()
- detach()
- All of the above
The explode() function in R can be used to explode segments in a pie chart. By specifying a vector of values, the explode() function moves specific segments away from the center of the pie chart, highlighting or separating them for emphasis.
How do you perform a logical 'AND' operation in R?
- Using the '&' operator
- Using the '&&' operator
- Using the 'AND' keyword
- All of the above
In R, you can perform a logical 'AND' operation using the '&' operator. The '&' operator returns 'TRUE' if both operands are 'TRUE', and 'FALSE' otherwise. For example, 'TRUE & FALSE' would evaluate to 'FALSE'.
The switch() function in R can be used as an alternative to multiple ________ if statements.
- nested
- vectorized
- case-when
- all
The switch() function in R can be used as an alternative to multiple nested if statements. It allows you to match a given expression to a set of predefined cases and execute the corresponding code block based on the matching case. This provides a more concise and readable alternative to using multiple nested if statements for handling multiple conditions.
In R, the escape sequence for a tab character is ________.
- n
- t
- r
- b
In R, the escape sequence for a tab character is t. For example, "HellotWorld" would result in the string "Hello World" with a tab space between "Hello" and "World".
The ________ function in R calculates the standard deviation of a numeric vector.
- sd()
- standard_deviation()
- stdev()
- variance()
The sd() function in R is used to calculate the standard deviation of a numeric vector. For example, if x is a numeric vector, sd(x) would return the standard deviation of the elements in x.
The _________ package in R can be used for advanced data reshaping and aggregation.
- dplyr
- ggplot2
- reshape2
- tidyr
reshape2 is a powerful package in R that provides methods to reshape your data between long and wide formats, as well as facilitating the aggregation of your data.
Can you describe a scenario where you would need to use a for loop in R?
- When performing iterative calculations
- When reading data from a file
- When creating plots and visualizations
- When installing packages in R
You would need to use a for loop in R when performing iterative calculations. For example, if you want to calculate a Fibonacci series, perform simulations, or generate a sequence of numbers based on specific conditions, a for loop allows you to repeat the necessary computations.
Imagine you're working with a large dataset in R and you need to remove a common prefix from a set of strings. How would you do it?
- Use the str_remove() function from stringr package
- Use the gsub() function
- Use the sub() function
- All of the above
All the options mentioned are ways to remove a common prefix from a set of strings. str_remove() from stringr, gsub(), and sub() from base R could all be used to achieve this, given the correct pattern and replacement arguments.
In R, to access the first column of a data frame named df, you would use ______.
- df$1
- df[, 1]
- df[1, ]
- df[[1]]
To access the first column of a data frame named df, you would use df[, 1]. The comma indicates that you want all rows and the number 1 specifies the first column.
When we assign a new value to an existing variable in R, the previous value is ________.
- Ignored
- None of the above
- Preserved
- Replaced
In R, when we assign a new value to an existing variable, the previous value is replaced. There's no built-in way to preserve the previous value when reassigning a variable in R.