The primary use case for nested functions in R is to encapsulate helper functions within a larger function. Nested functions can help in reducing code duplication, improving code modularity, and organizing related functionality together. They are especially useful when implementing complex algorithms or workflows that require multiple steps or subroutines.

In R, "==" is a comparison operator used to test for equality, while "=" is used for assignment, especially in the context of function arguments. However, "<-" is more commonly used for assignment.

To calculate the mean of each row in a matrix in R, you would use the rowMeans() function. The rowMeans() function computes the mean values across each row of the matrix.

The hist() function in R can be used to generate a histogram of a numeric vector. The hist() function divides the range of the data into equal intervals called bins and counts the number of observations falling into each bin, creating a visual representation of the distribution of the data.

When working with a large data set in R and aiming to create a bar chart that clearly communicates the key findings, it is important to simplify the chart by focusing on the most important categories. Use distinct colors or patterns to enhance differentiation between the bars. Provide clear labels and a legend to ensure better understanding of the chart. The combination of these approaches will help create an effective bar chart that effectively communicates the key findings.

The loess() function in R can be used to fit a smooth line to a scatter plot. It uses the locally weighted scatterplot smoothing technique to estimate a smooth curve that captures the general trend in the data.

In R, an array is created using the array() function. The array() function allows you to specify the values of the array, the dimensions, and other parameters such as dimension names. You can pass a vector of values and specify the dimensions to create the desired array structure.

You would prefer to use 'paste0()' over 'paste()' in R when you want to concatenate strings without a separator. The 'paste0()' function is a variation of the 'paste()' function that does not include a separator by default.

In R, the break keyword is used to prematurely exit a for loop. When encountered, the break statement immediately terminates the loop and execution continues with the next statement after the loop.

In R, the is.matrix() function can be used to check if an object is a matrix. It returns TRUE if the object is a matrix and FALSE otherwise. This function is useful for verifying the type of an object before applying operations specific to matrices.