In R, the nchar() function is used to determine the number of characters in a string. For example, nchar("Hello") would return 5.

The plot() function is commonly used to create a basic scatter plot in R. It can be used to visualize the relationship between two numeric variables by plotting the data points as individual points on the graph.

A vector in R is a sequence of data elements of the same basic type. Members in a vector are officially called components. However, R also has other data structures like lists, matrix, and dataframe which can hold multiple data types or more complex data.

All of the mentioned techniques can be used in R to visualize high-dimensional data. Scatter plots can encode additional dimensions through color or size. Parallel coordinate plots can show relationships between multiple variables. Dimensionality reduction techniques like PCA or t-SNE can project high-dimensional data into lower dimensions for visualization.

To write a function in R that uses a global variable, you would define the global variable outside of the function and access it within the function. Since global variables are accessible from anywhere in the program, the function can directly reference and modify the global variable as needed.

To create a function in R that checks if a number is prime, you can use the following code: is_prime <- function(n) { if (n <= 1) { return(FALSE) } for (i in 2:sqrt(n)) { if (n %% i == 0) { return(FALSE) } } return(TRUE) }. The function takes a number n as input and iterates from 2 to the square root of n, checking if any of these numbers divides n. If a divisor is found, the function returns FALSE; otherwise, it returns TRUE.

Logical operations in R are commonly used in situations such as checking conditions in control flow statements, filtering data based on specific criteria, and creating boolean variables for flagging or indicating certain conditions.

In R, the operator != is used to check if two values are not equal. For example, 3 != 4 would return TRUE.

In R, the rbind() function can be used to combine several vectors into one. The rbind() function combines vectors by binding them row-wise, creating a new vector with the elements from each input vector arranged in rows.

R stores all variables in RAM (Random Access Memory). This includes vectors, lists, data frames, and other data structures. This is part of what allows R to perform operations on data very quickly, but it also means that R can be memory-intensive, especially when working with large datasets.